Patient monitoring system

ABSTRACT

A wireless medical telemetry system includes at least one wireless patient monitor configured to collect patient vital signs data, and at least one central station adapted to establish communications with the at least one patient monitor via a wireless transceiver, and to receive the patient vital signs data from the at least one patient monitor. The at least one patient monitor is operable by a user to transmit an end-communications signal to the at least one central station, and the at least one central station is configured to terminate the communications with the at least one patient monitor in response to the end-communications signal. A method for monitoring a patient includes the steps of (i) establishing wireless communications between a patient monitor and a wireless transceiver connected to a remote central station, (ii) collecting, at the patient monitor, vital signs data from a patient and communicating the vital signs data to the central station via the wireless transceiver, (iii) communicating an end-communications signal from the patient monitor to the central station, and (iv) terminating the communications by the central station in response to the end-communications signal. There is also a system for monitoring the vital signs of a patient from a selected remote location.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional PatentApplication Ser. No. 60/205,412, filed May 19, 2000 and entitled PATIENTMONITORING SYSTEM. The subject matter of this application isincorporated herein by this reference.

FIELD OF THE INVENTION

[0002] The present invention relates generally to monitoring the vitalsigns of one or more patients, and more particularly to a system andmethod for monitoring patients via wireless communications.

BACKGROUND

[0003] Devices for measuring various physiological parameters, or “vitalsigns,” of a patient such as temperature, blood pressure, heart rate,heart activity, etc., have been a standard part of medical care for manyyears. Indeed, the vital signs of some patients (e.g., those undergoingrelatively moderate to high levels of care) typically are measured on asubstantially continuous basis to enable physicians, nurses and otherhealth care providers to detect sudden changes in a patient's conditionand evaluate a patient's condition over an extended period of time.However, since most hospitals and other medical facilities care fornumerous patients assigned to numerous different rooms, it can bedifficult for a finite number of clinicians to monitor multiple patientson a continuous basis. In an effort to alleviate this problem, somemedical monitoring systems have been developed to enable the vital signsdata collected from patients to be conveyed to a central location,thereby allowing one or a few clinicians to simultaneously monitormultiple patients in different locations. However, many of such priorsystems have not allowed the monitored patients to move about thehospital. Although a few “mobile” monitoring systems have beenattempted, such systems are difficult to use and prone to failureresulting in the loss of a patient's vital signs data.

SUMMARY

[0004] A wireless medical telemetry system includes at least onewireless patient monitor configured to collect patient vital signs data,and at least one central station adapted to establish communicationswith the at least one patient monitor via a wireless transceiver, and toreceive the patient vital signs data from the at least one patientmonitor. The at least one patient monitor is operable by a user totransmit an end-communications signal to the at least one centralstation, and the at least one central station is configured to terminatethe communications with the at least one patient monitor in response tothe end-communications signal.

[0005] The invention may also been characterized as a method formonitoring a patient that includes the steps of (i) establishingwireless communications between a patient monitor and a wirelesstransceiver connected to a remote central station, (ii) collecting, atthe patient monitor, vital signs data from a patient and communicatingthe vital signs data to the central station via the wirelesstransceiver, (iii) communicating an end-communications signal from thepatient monitor to the central station, and (iv) terminating thecommunications by the central station in response to theend-communications signal.

[0006] The invention may also be characterized as a system formonitoring the vital signs of a patient from a selected remote location.Other characterizations of the invention and the advantages of thepresent invention will be understood more readily after a considerationof the drawings and the Detailed Description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a fragmentary, schematic illustration of an exemplarymedical telemetry network according to the present invention in thecontext of a hospital.

[0008]FIG. 2 is a fragmentary, schematic diagram of a system formonitoring a plurality of patients in accordance with the presentinvention.

[0009]FIG. 3 is a front elevation view of an exemplary centralmonitoring station according to the present invention.

[0010]FIG. 4 is a schematic diagram of an exemplary system formonitoring patients according to the present invention.

[0011]FIG. 5 is a front isometric view of an exemplary patient monitoraccording to the present invention.

[0012]FIG. 6 is a front isometric view of another exemplary patientmonitor according to the present invention.

[0013]FIG. 7 is a schematic, functional block diagram of an exemplarypatient monitor according to the present invention.

[0014]FIG. 8 is an exemplary image for display on a display screenaccording to the present invention.

[0015]FIG. 9 is similar to the image of FIG. 8 but modified to include amessage region for display on a display screen according to the presentinvention.

[0016]FIG. 10 is similar to the image of FIG. 8 but modified to includea user-interface for display on a display screen according to thepresent invention.

[0017]FIG. 11 is a flowchart illustrating an exemplary rendezvousprocess according to the present invention.

[0018]FIG. 12 is a flowchart illustrating an exemplary communicationsconfiguration process according to the present invention.

[0019]FIG. 13 is an exemplary image for display on a display screen, andincluding a user-interface operable to select a primary central stationin accordance with the present invention.

[0020]FIG. 14 is an exemplary image for display on a display screen, andincluding a user-interface operable to confirm a monitoringconfiguration in accordance with the present invention.

[0021]FIG. 15 is an exemplary image for display on a display screen, andincluding a user-interface operable to identify a patient beingmonitored in accordance with the present invention.

[0022]FIG. 16 is an exemplary image for display on a display screen, andincluding a user-interface operable to select a primary central stationin accordance with the present invention.

[0023]FIG. 17 is an exemplary image for display on a display screen, andincluding a user-interface operable to change alarm condition parametersin accordance with the present invention.

[0024]FIG. 18 is an exemplary image representing ECG data from a singleelectrode for display on a display screen according to the presentinvention.

[0025]FIG. 19 is an exemplary image representing ECG data from pluralelectrodes for display on a display screen according to the presentinvention.

[0026]FIG. 20 is an exemplary image indicating an alarm condition fordisplay on a display screen according to the present invention.

[0027]FIG. 21 is a schematic illustration of a system for monitoring apatient at plural central stations according to the present invention.

[0028]FIG. 22 is a flowchart diagram of an exemplary method formonitoring a patient at a central location in accordance with thepresent invention.

[0029]FIG. 23 is a flowchart diagram of another exemplary method formonitoring a patient at a central location in accordance with thepresent invention.

[0030]FIG. 24 is a flowchart diagram of another exemplary method formonitoring a patient at a central location in accordance with thepresent invention.

[0031]FIG. 25 is a flowchart diagram of another exemplary method formonitoring a patient at a central location in accordance with thepresent invention.

[0032]FIG. 26 is a flowchart diagram of another exemplary method formonitoring a patient at a central location in accordance with thepresent invention.

DETAILED DESCRIPTION

[0033] From an overview, and as will be described in detail below, asystem and method for monitoring patients is described that affordscommunication between plural patient monitors and plural centralmonitoring stations. The system and method is designed to allow thepatient monitors to communicate with the central monitoring stations byusing any known communication connection (such as to-be-described accesspoints) located anywhere using any known communications technology (suchas the IEEE 802.11 standard for wireless communication) that provides acommunication channel. The to-be-described system and method also makesit possible for a clinician to view patient data on a display componentof the patient monitor via any known communication channel such as theInternet. For example, the clinician could view patient data using knownweb browsers.

[0034] The to-be described system and method also includes a so-called“rendezvous process” of establishing communications with one or morecentral stations. As will be shown in connection with the description ofFIG. 11, the rendezvous process may be carried out in any of a varietyof different ways, and may vary depending on whether wireless or wiredcommunications are used, as well as on whether the patient monitor isestablishing a new communications connection or reestablishing priorcommunications which were lost or terminated.

[0035] The patient monitors of the to-be-described system are alsoconstructed to function both as part of a network of patient monitorsand central stations, as well as stand-alone patient monitors.

[0036] Turning now to details, a system for monitoring patientsaccording to the present invention is indicated generally at 20 inFIG. 1. System 20 includes one or more patient monitors 22, each adaptedto collect vital signs data from a patient. System 20 also includes oneor more central monitoring stations 24 adapted to communicate with thepatient monitors and receive, process and store the vital signs data.Thus, physicians, nurses and other health-care personnel (hereinafterreferred to collectively as clinicians) are able to monitor a pluralityof patients simultaneously and continuously from one or more centrallocations. As will be described in more detail below, patient monitors22 and central stations 24 are coupled to communicate using wirelesstransmissions within a medical telemetry network, thereby allowing apatient to move about inside or outside a monitoring facility withoutloss of central monitoring.

[0037] In the exemplary embodiments shown and described herein, system20 is configured for use in a hospital. However, it will be appreciatedthat system 20 also may be used in a variety of other environmentsincluding: (i) other types of medical facilities, research facilities,senior-care facilities, hospices, field hospitals, etc.; and (ii) typesof non-medical facilities and environments such as patient residences,retail stores, or patient locations outdoors. Therefore, it will beunderstood that the description herein encompasses medical telemetrysystems for use in all such environments.

[0038] System 20 may be configured to provide patient monitoring withinselected regions of a facility or throughout the facility. In theexemplary embodiment depicted in FIG. 1, system 20 is configured withpatient monitors and central stations on multiple floors of a hospital.System 20 includes one or more wireless transceivers 26 disposed withinthe facility and configured to communicate with patient monitors 22 viawireless transmissions. The wireless transceivers are configured toconvey communications between the patient monitors and the centralstations. As a result, centralized patient monitoring will extendwherever wireless transceivers 26 are disposed within a facility.

[0039] Transceivers 26 may be also be characterized astransmitter/receivers 26, i.e. any device capable of transmitting andsending communication signals, whether it be a device operable for awired application or a device operable for a wireless application.However, for purposes of the remainder of the description of theexemplary embodiment, the term transceivers will be used to describe forthe wireless application being described.

[0040] Each floor may include a single central station (as shown on theupper floor in FIG. 1) or plural central stations (as shown on the lowerfloor). Alternatively, a single central station may be configured tomonitor patients on multiple floors. In many hospitals, central stations24 are assigned to sections within the hospital that perform differentfunctions rather than to particular floors. For example, one or morecentral stations may be configured to monitor patients admitted to theIntensive Care Ward, one or more different central stations may beconfigured to monitor patients admitted to the Emergency Room, while oneor more other central stations may be configured to monitor patientsadmitted to the Maternity Ward, etc. Regardless of how the centralstations are arranged or assigned, system 20 may be configured to allowany patient monitor 22 to be monitored by any central station 24.

[0041] In addition to allowing multiple remote patients to be monitoredat a central location, system 20 may also be configured to allowclinicians to view information about a patient's condition from variouslocations inside and/or outside the hospital. For example, in theembodiment depicted in FIG. 1, system 20 includes one or moreannunciating devices 28, each having a display adapted to identify aparticular patient (e.g., by name, room number, etc.) and to providesome information concerning the patient's condition. Typically,annunciating devices 28 are used to indicate alarm conditions for amonitored patient. Alternatively, the annunciating devices may beconfigured to indicate the condition of selected patients regardless ofwhether an alarm condition exists. In addition to annunciator devices28, system 20 may also include other devices configured to enableclinicians to monitor a patient's condition at a location remote fromeither the patient or the central station. These other devices will bedescribed in more detail below.

[0042] System 20 may be implemented in many different forms andconfigurations using various types and combinations of components toprovide a variety of features and functions within the scope of theinvention. For clarity, the invention will be described below primarilyin the context of one particular exemplary embodiment. However, it willbe understood that the scope of the invention is not limited to theparticular embodiment described, but rather extends to all suchembodiments, forms, configurations, types and combinations.

[0043] Turning attention to FIG. 2, a schematic representation ofexemplary system 20 is shown. The system includes a medical telemetrynetwork 30 adapted to monitor a plurality of patients. In the exemplaryembodiment, network 30 includes a physical data transport structure 32(also referred to herein as a network) such as an Ethernet Local AreaNetwork (LAN) system. Alternatively, network 30 may be any of theelectrical and/or optical network communications structures known tothose of skill in the art. Alternatively, physical data transportstructure 32 may include any other suitable network structure, includinga wireless structure, whether now known or later developed. In anyevent, physical data transport structure 32 is adapted to interconnect aplurality of network components, and to transmit data communicationsbetween the components.

[0044] Although not shown in FIG. 2, it will be appreciated by those ofskill in the art that physical data transport structure 32 typicallywill include one or more devices adapted to connect the physicaltransmission lines together and route communications within thecommunications structure. Examples of such devices include switches,hubs, bridges, routers, and the like. Thus, as used her herein physicaldata transport structure 32 includes all such devices which may benecessary and/or beneficial to a particular implementation as well asthe physical communication lines.

[0045] Communications transmitted within network 30 typically complywith one or more standard data communication protocols which are knownto those of skill in the art. As will be described in more detail below,the components of exemplary network 30 use a variety of standardcommunication protocols including the Transmission ControlProtocol/Internet Protocol (TCP/IP) suite, User Datagram Protocol (UDP),etc. Use of standard communication protocols allows a variety ofdifferent components to be connected to communicate over the network.Furthermore, use of standard communication protocols enables the use ofstandard routers, switches and other network devices as mentioned above.Alternatively or additionally, the components may communicate using oneor more non-standardized protocols adapted for medical telemetry or aparticular application.

[0046] Network 30 includes one or more central stations 24, eachconnected to communicate via physical data transport structure 32 andconfigured to monitor a plurality of patients. It will be appreciatedthat central stations 24 may take any one or more of a variety ofdifferent forms. In the exemplary embodiment, each central station takesthe form of a computer workstation configured to communicate viaphysical data transport structure 32 and monitor a plurality ofpatients. Central stations 24 may be any suitable type of centralstation such as the ACUITY® central station available from Welch AllynProtocol, Inc. of Beaverton, Oreg. The ACUITY® central station is aversion of the invention claimed in U.S. Pat. No. 5,319,313 to Welch etal.

[0047] One example of a central station in accordance with the presentinvention is shown in FIG. 3. Exemplary central station 24 includes aprocessing module 34 having at least one processor (not shown) and atleast one data storage unit (not shown). The processor is adapted toexecute software stored in the data storage unit to communicate withpatient monitors, analyze patient data, etc. Central station 24 alsoincludes a plurality of display devices such as display monitors 36.Alternatively, central station 24 may include a single display monitor.In any event, display monitors 36 are connected to processing module 34and adapted to display vital signs data collected from a plurality ofpatients. Typically, central station 24 also includes one or more inputdevices 38 (e.g. keyboard, cursor control, mouse, remote control,touch-screen, etc.) operable by a user to control the central station.Central station 24 may also include one or more audio input/output (i/o)devices such as speakers, microphones, sirens, buzzers, etc., adapted toproduce an audible message to a user of the central station n. Those ofskill in the art will appreciate that central stations 24 may have avariety of different configurations within the scope of the invention.

[0048] Central stations 24 are typically disposed at selectedcentralized locations within the hospital such as at nursing stations,etc. Each central station is adapted to receive patient vital signs datafrom one or more patient monitors via physical data transport structure32. The central stations are controllable by a user to display selectedinformation concerning each monitored patient on the display monitor.This allows clinicians to view the information collected by a patientmonitor at the centralized location. Additionally, central stations 24may be configured to simultaneously display data from a plurality ofpatients, thereby enabling a single clinician to watch over severalpatients at different locations. In addition to communicating withpatient monitors, central stations 24 may also be configured tocommunicate with other central stations within the network. Thus, forexample, patient data received at one central station may be forwardedto a different central station. This allows two or more clinicians atdifferent locations to simultaneously monitor a single patient.Communications among different central stations will be described inmore detail below.

[0049] Turning attention back to FIG. 2, network 30 may also include oneor more database systems 40 configured to store patient information.Database system 40 is connected to physical data transport structure 32and accessible by central stations 24 to store and retrieve data.Patient information stored on database system 40 may include a varietyof information concerning each patient including personal information,medical history, room location, etc. Typically, the central stations areconfigured to access database system 40 to identify patients who areadmitted to the hospital and display a list of the patients on displaymonitor 36. This allows a clinician to associate vital signs datareceived from a particular patient monitor with the correspondingpatient. The central station also may be configured to store on databasesystem 40 some or all of the vital signs data received from the patientmonitors. While database system 40 is depicted in FIG. 2 as a single,separate system connected to physical data transport structure 32, itwill be appreciated that other configurations are also within the scopeof the invention. For example, database system 40 may be multipledatabases distributed around network 30. Alternatively, database system40 may be contained within some or all of the central stations.Typically, database system 40 is a system or network of data storagedevices, some of which are contained within the central stations andothers existing separately in network 30. In any event, it will beappreciated that database system 40 may be any of the various databasesystems or structures such as are known to those of skill in the art.

[0050] As discussed above, central stations 24 are configured tocommunicate with a plurality of patient monitors via physical datatransport structure 32. Communications between the central stations andpatient monitors may be via wire (i.e., transmitted over a physical lineadapted to convey electrical or optical signals), or may be wirelesscommunications. Considering first the wire communications, one or morepatient monitors 22 may be connected to physical data transportstructure 32 either directly (e.g., through an Ethernet connection), orindirectly through a terminal server 42 or similar device. Terminalserver 42 includes a plurality of ports adapted to receive connectionsfrom the patient monitors. In addition, the terminal server is alsoconnected to physical data transport structure 32. The terminal serveris configured to receive communications from the patient monitors andforward the communications to the appropriate central station viaphysical data transport structure 32. Similarly, the terminal serveralso is configured to receive communications from the central stationsvia physical data transport structure 32 and convey the communicationsto the appropriate patient monitor. Terminal server 42 may be any of avariety of terminal servers such as are known to those of skill in theart. Any known wire or wireless communication technologies may be usedto perform the functions described above.

[0051] In TCP/IP based networks, communications between central stationsand patient monitors are directed to the appropriate component usingnetwork addresses such as IP addresses as well as hardware addresses.Typically, each central station is assigned a unique IP address and allcommunications to and from a particular central station will include theparticular station's IP address. Similarly, all patient monitors whichare directly connected to physical data transport structure 32 areassigned a unique IP address. In contrast, patient monitors which areconnected to physical data transport structure 32 through a terminalserver typically do not have a unique IP address. Instead, the terminalserver has an IP address with which to communicate with the othercomponents connected to physical data transport structure 32.Communications from a patient monitor are transmitted to the terminalserver with the IP address of the destination component (e.g., a centralstation). The terminal server appends its own IP address to eachcommunication and then forwards the communication to the appropriatecomponent. Similarly, communications to a patient monitor aretransmitted with the terminal server's address as the destinationaddress. Upon receipt, the terminal server forwards the communicationsto the appropriate patient monitor.

[0052] As shown in FIG. 2, network 30 also includes one or more wirelesstransceivers 26, which are hereinafter referred to as access points 26.Each access point is connected to physical data transport structure 32and configured to communicate with the other components connected tophysical data transport structure 32. Each access point includes thesoftware necessary to communicate via physical data transport structure32 using the selected communications protocols of network 30 (e.g.,TCP/IP, UDP, etc.). In the exemplary embodiment, each access point has aunique IP address that may be permanently coded into the access point,or may be assigned by a server such as described below. The accesspoints also are configured to communicate, via wireless transmissions,with components which are not directly connected to physical datatransport structure 32. Each access point includes a wireless receiverto receive wireless communications, and a wireless transmitter totransmit wireless communications.

[0053] It will be appreciated that access points 26 may be configured tocommunicate using any of a variety of different wireless transmissiontechnologies depending on the application, environment, governmentalregulations, etc. In the exemplary implementation, the access points areconfigured to communicate with the patient monitors (described in moredetail below) as well as other devices under the IEEE 802.11 standardusing Frequency Hopping Spread Spectrum (FHSS) technology in the 2.4 GHzISM (Industrial, Scientific, and Medical) band. The IEEE 802.11communications standard is well known to those of skill in the art.Access points 26 essentially act as network bridges between the wirelesscomponents of network 30 and wired network physical data transportstructure 32. Other wireless transmission, or communication,technologies known to those skilled in the art may be used includingIEEE 802.11a, IEEE 802.11b, and IEEE 802.15.

[0054] Exemplary access points 26 may be any wireless transceiversadapted to communicate using the IEEE 802.11 FHSS technology. Oneexample of a suitable access point is the SPECTRUM24 AP 3021 availablefrom Symbol Technologies of Holtsville, N.Y. In other implementationsand embodiments, access points 26 may be selected which are configuredto communicate using other technologies. In any event, the access pointsusually are configured to simultaneously communicate with a plurality ofpatient monitors and/or other wireless devices. For example, the AP 3021access points are adapted to simultaneously communicate with up toapproximately 15 patient monitors.

[0055] Each access point typically has a range within which it cancommunicate with wireless devices. The range will vary depending on thepower of the wireless transmitter, environmental conditions, etc.Typically, the access points are arranged within the hospital so that atleast one access point is able to communicate with a patient monitor atany point within a defined region of the hospital. For example, if it isdesired that wireless patient monitors be used on a particular floor ofthe hospital, then sufficient access points are provided and positionedso that every location on the particular floor is within the range ofone or more access points. This ensures that a patient associated with apatient monitor can move about the hospital floor without loss ofcentral monitoring. It will be understood that the access points may bearranged to provide wireless coverage within a defined region that isless than an entire floor of the hospital. Alternatively, the accesspoints may be arranged to provide coverage for regions that spanmultiple floors (whether or not adjacent) and/or multiple buildings.

[0056] As will be discussed in more detail below, patient monitors andother wireless devices communicate over physical data transportstructure 32 by first associating with an access point. Once a patientmonitor has associated with a particular access point, communicationsbetween the patient monitor and components on physical data transportstructure 32 are conveyed by the particular access point. However, asthe patient monitor moves out of range of the particular access pointand into the range of another access point, the patient monitorassociates with the other access point and subsequent communicationsbetween the patient monitor and components on physical data transportstructure 32 are conveyed by the other access point.

[0057] Use of FHSS technology allows access points to be positioned sothat the ranges of the access points overlap. Such an arrangementprovides for geographic redundancy in the event an access point fails.In addition, overlapping the access point ranges increases themonitoring capacity within the defined region or selected portions ofthe defined region. The access points typically are configured tocommunicate with one another to minimize or prevent interference. Theaccess points may also be configured to manage and balance thecommunication loads experienced by each access point. In addition, oneor more of the central stations may be configured to control the accesspoints to balance communication loads.

[0058] It will be appreciated that in many implementations thecommunication of patient information by wireless transmission must besecure and confidential. These security needs may be met in any of avariety of ways known to those of skill in the art. For example, the802.11 standard provides WEP (Wired Equivalent Privacy) which encryptsthe wireless transmissions. In addition, some implementations mayutilize additional security measures such as end-to-end data encryption,etc.

[0059] In the exemplary embodiment, network 30 also includes a router 44or similar device connected to physical data transport structure 32between a first portion 46 and a second portion 48 of physical datatransport structure 32. Components connected to the first portion areassigned IP addresses corresponding to a first subnet, while componentsconnected to the second portion are assigned IP addresses correspondingto a second subnet. First portion 46 is connected to central stations24, database system 40, terminal server 42 and the other components ofnetwork 30 which are configured for wired communications via physicaldata transport structure 32. Second portion 48 is connected to accesspoints 26. Thus, first portion 46 may be seen as a wired portion ofnetwork 30, while second portion 48 may be seen as a wireless portion ofnetwork 30. Use of router 44 between wired portion 46 and wirelessportion 48 allows the wireless portion of the network to be isolatedfrom the communication traffic on the wired portion of the network.Communications between patient monitors and central stations are passedby router 44 from wired portion 46 to wireless portion 48 and viceversa. However, communications between central stations and/or othercomponents connected to wired portion 46 are not passed to wirelessportion 48. Alternatively, wired portion 46 and wireless portion 48 maybe directly connected to the same subnet, eliminating the need for arouter.

[0060] In the exemplary embodiment, network 30 also includes at leastone server system 50 connected to the wireless portion of the network.As will be discussed in more detail below, server system 50 is adaptedto assign IP addresses to the patient monitors once the patient monitorsassociate with an access point. Server system 50 may be configured toassign IP addresses according to any suitable protocol such as theDynamic Host Configuration Protocol (DHCP), the Bootstrap Protocol(BOOTP), etc. It will be appreciated that server system 50 is connectedon the wireless portion of physical data transport structure 32 relativeto router 44 to ensure that requests for IP addresses from the patientmonitors are received at server system 50. Alternatively, router 44 maybe configured to convey the requests for IP addresses between thewireless and wired portions, in which case server system 50 may beconnected on the wired portion of the network.

[0061] Server system 50 may be a separate computer system adapted tomanage and assign IP addresses only, or it may be configured to performother functions including network management, etc. In alternativeembodiments, one of central stations 24 is configured to perform thefunctions of server system 50, thereby alleviating the need for aseparate server system 50. In such embodiments, the central stationwhich is configured to assign IP addresses in the alternative embodimentshould be connected to the wireless portion of network 30 unless router44 is adapted to pass requests for an IP address to the wired portion ofthe network.

[0062] Network 30 may also include one or more wireless communicationdevices referred to herein as clinician terminals 52. The wirelessclinician terminals may take any one of a variety of different formsincluding Personal Digital Assistants (PDA's), Internet Protocol (IP)telephones, portable computers, etc. Clinician terminals 52 includewireless transceivers (e.g., RF network cards) that are configured toassociate with access points 26. The clinician terminals also includesuitable software executable by the terminals to communicate with thecentral stations via access points 26. The clinician terminals may alsobe configured to perform a variety of functions such as receiving anddisplaying patient vital signs data from the central station,transmitting control instructions to the central station to control aselected aspect of the central station, transmitting controlinstructions to the central station for forwarding to a patient monitorto control selected aspects of the patient monitor, sending andreceiving textual messages, receiving and acknowledging alarm signals,etc. In the exemplary embodiment, clinician terminals 52 are configuredto function as quasi-central stations, by displaying patient vital signsdata and providing a user-interface operable by the clinician to controlthe patient monitor.

[0063] Clinician terminals 52 enable physicians, nurses and others toobtain information concerning a patient from any location within thedefined region of network 30, rather than only at the patient's locationor at a central station. Thus, for example, a clinician several floorsaway from a patient can receive a notification of an alarm at thepatient monitor associated with the patient. Further, the clinician canevaluate the patient's condition from the vital signs data without goingto the patient's location. The clinician may then take appropriateaction depending on the patient's condition. It will be appreciated thatclinician terminals 52 enable clinicians to work more efficiently andeffectively, and to care for a larger number of patients than wouldotherwise be possible. Furthermore, while the clinician terminals mayinclude paging functions, the clinician terminals provide substantiallymore information to the clinicians than pagers.

[0064] Exemplary telemetry network 30 also is connected to the maincomputer network 54 of the hospital, referred to hereinafter as thesecondary or non-telemetry network. Secondary network 54 typicallyincludes a plurality of computer terminals 56, database systems 58, etc.The secondary network interconnects the hospital's administrativecomputers and other non-telemetry components. Typically, secondarynetwork 54 is connected to telemetry network 30 through router 44. Thisisolates the telemetry network from non-telemetry communication traffic,while allowing devices connected to the non-telemetry network to accesspatient vital signs data. Similarly, users of central stations 24 areable to access information on the secondary network as needed. In someimplementations it may be desirable to provide security measures toensure that only authorized users of secondary network 54 are able toaccess telemetry network 30. Any of a variety of suitable securitymeasures may be employed as are known to those of skill in the art.

[0065] Network 30 may also be connected to a communications networkexternal to the hospital such as an extranet, virtual private network,Wide Area Network (WAN), etc. In the exemplary implementation, network30 is connected to the Internet 60. Typically, network 30 is connectedto the Internet via a firewall 62 or other suitable security device torestrict access to patient data and other confidential information.

[0066] As shown in FIG. 4, the telemetry network of one hospital 64 maybe connected to the telemetry network and/or the secondary network ofone or more other hospitals 66 in remote locations. The telemetrynetwork may be connected to the remote hospitals via Internet 60 or viaa direct, non-public network 68 such as is known to those of skill inthe art. Central stations 24 of hospital 64 may be configured totransmit patient information including vital signs data to centralstations or other computers in remote hospital 66. Similarly, thecentral stations of hospital 64 may be configured to request and receivepatient information including vital signs data from remote hospitals 66.It will be appreciated that communication of patient information betweenremote hospitals allows clinicians to participate in consultations withtheir remote colleagues more effectively and efficiently.

[0067] In the implementation described above, access points 26 werearranged within the hospital to provide wireless monitoring in a definedregion of the hospital. In alternative implementations, the definedregion may extend outside the hospital. For example, system 20 mayinclude one or more access points 26 which are positioned outside of thehospital, as shown in FIG. 4. The access points are connected toInternet 60 and configured to transmit the patient vital signs data tonetwork 30 and one or more central stations 24. This allows patients tomove outside of the hospital without loss of continuous centralmonitoring. So long as the patient remains within the range of at leastone access point, the patient's vital signs data may be displayed on acentral station as if the patient was still in the hospital. Similarly,emergency response workers could connect a patient monitor to anaccident victim so that the hospital can monitor the victim's conditionwhile the victim is transported to the hospital.

[0068] It will be appreciated that placement of access points outside ofthe hospital also allows clinicians to access patient data when outsidethe hospital. As shown in FIG. 4, one or more clinician terminals 52 mayassociate with the external access points to view patient informationand control the patient monitor connected to a patient. This providesclinicians with more flexibility to leave the hospital while continuingto monitor their patients at the hospital (or patients outside thehospital). Alternatively, clinicians may monitor patients using personalcomputers 70 or similar devices configured to connect to Internet 60 andcommunicate with central stations at the hospital. Computers 70 may belocated anywhere a connection is available that provides a communicationchannel using any communication technology. For example, computers 70may be located anywhere a connection to the Internet is available.Alternatively, computers 70 may be configured to associate with anexternal access point and communicate via wireless transmissions.

[0069] As discussed above, the defined region of monitoring will extendoutside the hospital wherever access points 26 are positioned. In areaswhere the external network of access points is undeveloped, patientmonitors 22 and/or clinician terminals 52 may be configured tocommunicate using other wireless communication technologies. Forexample, the implementation depicted in FIG. 4 includes a CellularDigital Packet Data (CDPD) network 72, such as is currently used forcellular telephone and other communications. Patient monitors 22 and/orclinician terminals 52 may be configured to communicate with centralstations in hospital 64 via CDPD network 72. Thus, for example, apatient might be discharged to go home while continuing to be monitored.It will be appreciated that this alleviates the need to have newwireless networks installed throughout a geographic region, since thecomponents of system 20 are configured to communicate using preexistingnetworks. An alternate implementation (undepicted) would be to use whatis known as a Global System Mobile (GSM), or any other availablewide-reaching communication system.

[0070] Considering patient monitors 22 in more detail, it will beappreciated that there are a variety of different patient monitorsavailable and suitable for use with system 20. System 20 may include oneor more patient monitors of a single type, or may include multiple typesof patient monitors, each configured to communicate with one or morecentral stations. For example, the exemplary embodiment of system 20depicted in FIGS. 1 and 2 includes a first type of patient monitor 22 aadapted to be carried or worn by a patient, and a second type of patientmonitor 22 b adapted to be mounted on a bed, wheelchair, etc, as well asbeing carried. Patient monitors 22 a and 22 b may be configured toperform the same monitoring functions or may be configured to performdifferent monitoring functions. In any event, each type of patientmonitor 22 is configured to collect vital signs data from a patient andcommunicate at least a portion of the vital signs data to a centralstation via physical data transport structure 32. Suitable patientmonitors are available from several manufacturers, including theMICROPAQ and PROPAQ patient monitors available from Welch AllynProtocol, Inc. of Beaverton, Oreg.

[0071] Turning attention now to FIG. 5, exemplary patient monitor 22 ais shown in more detail. The monitor includes a portable housing 80having one or more sensor input ports 82. The housing is sized to beheld by a clinician or patient, or to be worn by the patient using astrap, belt, or similar device. Sensor input ports 82 are adapted toreceive and connect to sensor cables 83. Each cable 83 is attached toone or more sensor assemblies (not shown). The sensor assemblies mayinclude any vital signs sensor assembly adapted to detect and/or measureselected vital signs data from a patient and transmit the vital signsdata via cables 83. Examples, of suitable sensor assemblies includeelectrocardiogram (ECG) sensor assemblies, non-invasive blood pressuresensor assemblies, invasive blood pressure sensor assemblies,temperature sensor assemblies, pulse oximetry sensor assemblies,respiration sensor assemblies, carbon dioxide sensor assemblies, etc.Suitable sensor assemblies are available from Welch Allyn Protocol, Inc.of Beaverton, Oreg. In any event, each sensor input port is adapted toreceive patient vital signs data from the sensor assembly attachedthereto.

[0072] Patient monitor 22 a also includes a display device such asdisplay screen 84 adapted to display the vital signs data or an imagerepresentative of the vital signs data. Exemplary display screen 84 isin the form of a liquid crystal display (LCD) device. Alternatively oradditionally to display screen 84, patient monitor 22 a may include anyother suitable display device such as a printer, one or more indicatorlights, light-emitting diodes, etc. The patient monitor also includesone or more input devices such as buttons 86 disposed on housing 80.Buttons 86 are operable by a user to input information into patientmonitor 22 a, as will be discussed in more detail below. In addition to,or in place of buttons 86, the patient monitor may include other typesof input devices including switches, knobs, etc. As a furtheralternative, display screen 84 may be a touch-screen adapted to inputinformation in response to contact by the user at selected locations onthe screen. While the exemplary embodiment will be described below ashaving input devices in the form of buttons, it will be understood thatany type of input device may be used.

[0073] Exemplary patient monitor 22 a further includes a batteryassembly 88 having one or more batteries. Battery assembly 88 ismountable in a battery compartment within housing 80. The batteriestypically are rechargeable, however non-rechargeable batteries may alsobe used. Although not shown in FIG. 5, patient monitor 22 a alsoincludes a controller, a memory device, and an on-board wirelesstransceiver, all operably disposed within portable housing 80. Aninternal antenna 90 is mounted within the housing and coupled to thewireless transceiver. Alternatively, antenna 90 may be disposedexternally to housing 80. An audio input/output device 92, (e.g.,speaker, microphone, buzzer, siren, etc.) is also disposed within thehousing and adapted to produce an audible notification to a clinician,patient, or other user of the monitor. An alternative to theinput/output device would be a bi-directional audio device.

[0074] As shown in FIG. 6, exemplary patient monitor 22 b includes aportable housing 94 adapted to attach to a bed, wheelchair or othersupport structure. Housing 94 includes one or more sensor input ports 82adapted to connect to sensor cables 83 and receive vital signs data fromone or more sensor assemblies (not shown). Similar to patient monitor 22a, patient monitor 22 b includes a display device such as display screen84 and one or more input devices such as buttons 86. Although not shownin FIG. 6, patient monitor 22 b also includes a battery assembly 88, anantenna 90, and an audio output device 92. As will be described in moredetail below, patient monitor 22 b also includes a controller, a memorydevice and an on-board wireless transceiver, all operably disposed inhousing 94.

[0075] Unlike patient monitor 22 a, patient monitor 22 b includes anoutput port 96 adapted to receive a hard-wired network connection cable98 such as an Ethernet, RS-232, modem line, or similar networkcommunications cable for connection to physical data transport structure32 or terminal server 42. Thus, patient monitor 22 b is configured tocommunicate with central stations 24 using either wirelesscommunications via its on-board wireless transceiver, or wirecommunications via output port 96. As will be discussed in more detailbelow, patient monitor 22 b may be configured to automatically switchbetween wire and wireless communications in various situations.

[0076] As mentioned above, each patient monitor 22 includes a controllerdisposed within the portable housing. It will be appreciated that any ofa variety of different computer controllers, micro-controllers, orprocessors, such as are known to those of skill in the art, may be used.The controller, indicated at 100 in FIG. 7, is operably coupled toreceive power from battery assembly 88. The controller may also beconfigured to receive power from other sources (e.g., AC line currentthrough a wall socket, DC current through photovoltaic cells, etc.).

[0077] Controller 100 is also connected to memory device 102. It will beappreciated that memory device 102 may be any one or a combination ofdevices adapted to store electronic information such as RAM, ROM, PROM,EPROM, etc. Memory device 102 may also include removable storage mediasuch as magnetic discs and tapes, optical discs, etc. In addition tostoring patient vital signs data, memory device 102 may be configured tostore one or more software control programs executable by controller 100to perform its various functions including receiving and analyzing vitalsigns data, presenting information to a user, etc. In addition, thesoftware will include the necessary programs for communicating withcentral stations 24 (e.g., TCP/IP, DHCP, etc.) While memory device 102has been depicted as a single device, those of skill in the art willappreciate that memory device 102 may be a plurality of either similaror different memory devices.

[0078] Controller 100 is also coupled to sensor ports 82 and configuredto receive vital signs data from the sensor assemblies via the sensorports. In addition, controller 100 may be configured to supply powerand/or suitable drive signals onto one or more of the sensor ports todrive the sensor assemblies attached to the ports. In any event, vitalsigns data received at controller 100 may be stored in memory device102, processed, discarded, and/or communicated immediately to a centralstation.

[0079] The controller is connected to control wireless transceiver 104and communicate with central stations 24 via the transceiver. Wirelesstransceiver 104 may be any of a variety of wireless transceivers whichare known to those of skill in the art. One example of a suitablewireless transceiver is the SPECTRUM24 LA 3021 PC card, available fromSymbol Technologies of Holtsville, N.Y. Alternatively, other wirelesstransceivers may be used. In any event, wireless transceiver 104 isconfigured to communicate with access points 26 using the appropriatecommunications protocol of network 30. The wireless transceiver isconnected to antenna 90 and transmits data received from controller 100to access points 26. Similarly, the wireless transceiver receivestransmissions from one or more access points and forwards thecommunications to the controller. The wireless communications betweenpatient monitor 22 and the central stations will be discussed in moredetail below.

[0080] In the case of patient monitor 22 b, controller 100 is alsoconnected to output port 96 and configured to communicate with centralstations 24 via the output port rather than via wireless transceiver104. Controller 100 may also include a network card or similar device(not shown) adapted to transmit and receive communications via outputport 96. For clarity, the description below assumes that patient monitor22 communicates with central stations 24 via wireless transceiver 104.However, it will be understood that, unless stated otherwise, and forpurposes of this description, communications via output port 96 areviewed as identical to communications via the wireless transceiver, andtherefore both types of communications are included within thedescription. A distinction between wireless and hard-wired communicationis that patient location (room) is known with hard-wired communication(via the network jack to which the monitor is connected) and not knownwith wireless communication. However, for purposes of this description,that distinction is not seen as pertinent and that is why communicationsvia output port 96 are viewed as identical to communications via thewireless transceiver.

[0081] Controller 100 is also connected to receive inputs from buttons86. The buttons are operable by a user of the patient monitor to inputinformation to the controller, as well as to control the controller.Each button may have a single function or may have a variety offunctions depending on such factors as the operating condition of thecontroller, status of the sensor assemblies, communications with acentral station, screen displays, etc. In the exemplary embodiment,controller 100 is configured to control the function of buttons 86 andto disable the buttons under defined conditions.

[0082] Controller 100 is configured to control display screen 84 todisplay an image representing the vital signs data. It will beappreciated that the image displayed on display screen 84 will varydepending on the vital signs data collected by the patient monitor.Additionally, exemplary controller 100 is configured to change thedisplay based on instructions received from the user via buttons 86. Forexample, the user might select between displaying a single ECG signalfrom a single electrode, or multiple ECG signals from multipleelectrodes. FIG. 8 shows an exemplary display screen 84 on which vitalsigns data is being displayed. A waveform region 106 of the displayshows an image representing the signal data received from an ECG sensorassembly. A numeric region 108 of the display shows images that providenumerical representations of the vital signs data (e.g., heart rate,oxygen saturation in the patient's blood, etc.). The display may alsoinclude a patient identifier 110 that uniquely identifies the patient,such as the patient's name, etc. FIG. 9 shows another exemplary displayscreen 84 similar to the one in FIG. 8. However, the display screenshown in FIG. 9 has been changed to include a message region 112 fordisplaying messages to a user. Similarly, FIG. 10 shows anotherexemplary display screen 84 in which the image has been changed toinclude a user-interface region 114. The user-interface region allows auser to enter information 5 and control the patient monitor by operatingbuttons 86. Control of the display screen will be described in furtherdetail below.

[0083] Controller 100 is also connected to control audio output device92 and/or other audible indicator devices to produce audible messages orsignals. The controller may be configured to control the audio outputdevice to produce audible signals under any one or more of a variety ofconditions. For example, controller 100 is typically configured toanalyze at least some of the vital signs data and produce an audiblealarm if the vital signs data is outside a selected nominal range. Theanalysis of vital signs data and detection of alarm conditions will bedescribed in further detail below.

[0084] While one exemplary functional embodiment of patient monitors 22has been depicted in FIG. 7 and described above, it will be appreciatedthat many other configurations are possible. Thus, the invention is notlimited to the exemplary embodiment described, but includes any patientmonitor configuration adapted to collect vital signs data from a patientand communicate the vital signs data to one or more central stations.

[0085] Typically, patient monitors 22 are configured to function asstand-alone devices capable of providing local patient monitoringregardless of whether the patient monitor is in communication with acentral station. The patient monitor may be configured to beginmonitoring immediately upon power-up and attachment of at least onesensor assembly. Alternatively, the patient monitor may be configured tobegin monitoring upon receipt of an actuation signal.

[0086] Patient monitors 22 are also configured to attempt to establishcommunications with one or more central stations and communicate thevital signs data to the central stations. In the exemplary embodiment,the patient monitors are configured to attempt to establishcommunications immediately at power-up and to continue the attempt untilcommunications are established. Alternatively, one or more of thepatient monitors may be configured to attempt to establishcommunications only in response to an instruction by a user and/or theoccurrence of selected conditions. Those of skill in the art willappreciate that the process of establishing communications with one ormore central stations, also referred to herein as the rendezvousprocess, may be carried out in any of a variety of different ways. Inaddition, the rendezvous process may vary depending on whether thepatient monitor is communicating through wireless or wirecommunications, as well as on whether the patient monitor isestablishing a new communications connection or reestablishing priorcommunications which were lost or terminated.

[0087] The rendezvous process of the exemplary embodiment isschematically illustrated in FIG. 11. The process begins withestablishing a connection to physical data transport structure 32 by anyone of several methods. Where patient monitor 22 is configured tocommunicate using only wireless communications, the patient monitorestablishes a connection to physical data transport structure 32 byassociating with an access point, as indicated at 200. It will beappreciated that the process of associating with an access point mayvary with varying configurations of the access point and/or varyingconfigurations of the patient monitor. In the exemplary embodiment,wireless transceiver 104 associates with a patient monitor according tothe IEEE 802.11 standard, and the details of that standard are known tothose skilled in the art. Certain features of the exemplary embodimentinclude that (i) the patient monitors can be used in any telemetrynetwork described herein (such as the 802.11-standard telemetry network)without user-adjustment of the communications frequency, and (ii) thepatient monitors automatically scan for access points and detectaccess-point configuration and synchronization information.

[0088] In addition, the wireless transceiver determines which accesspoints are within range of the patient monitor, and the currentcommunications load on the in-range access points. Using thisinformation, the patient monitor selects one of the in-range accesspoints with which to communicate, and begins the authentication processwhich is followed by the association process. Once the authenticationand association processes are complete, the connection between thepatient monitor and physical data transport structure 32 is established.

[0089] In the exemplary embodiment where communications over network 30conform to the IP protocol, each device must have an associated IPaddress with which to send and receive communications. In someembodiments, patient monitor 22 may have a permanently assigned IPaddress stored in memory device 102. Alternatively, patient monitor 22may not have an assigned IP address, and instead may be configured torequest an IP address upon establishing a connection with physical datatransport structure 32, as indicated at 202 and 204. Typically, patientmonitor 22 requests an IP address by transmitting a broadcast request toserver 50 using the appropriate protocol (e.g., DHCP, BOOTP, etc.). Therequest is answered by server 50, which responds by assigning thepatient monitor an IP address from a store of available IP addresses,and then transmitting a notification of the assignment to the patientmonitor. Alternatively, server 50 may store a pre-assigned IP addressfor each device, and respond with the corresponding pre-assigned IPaddress. Upon receiving the assigned IP address, the patient monitor isprepared to broadcast a request for communications to one or morecentral stations, as will be described in more detail below.

[0090] Where patient monitor 22 is adapted to communicate using eitherwireless or wire communications, the process for establishing aconnection to physical data transport structure 32 will vary dependingon whether a wireless or wire connection is established. In the formercase, the process may occur as described above, i.e., first associatingwith an access point, and then requesting an IP address if necessary.Alternatively, if a wire connection is to be established, the patientmonitor may be physically connected to a terminal server which isconnected to the network, as indicated at 206. It will be appreciatedthat the connection indicated at 206 may alternatively take other forms,such as a modem connection to a modem server, etc. In any case, once theconnection is established and any necessary hand-shaking between thepatient monitor and the terminal server is completed, the patientmonitor is prepared to broadcast a request for communications to one ormore central stations. Patient monitor 22 will communicate using the IPaddress of the server, and therefore is not required to have its own IPaddress.

[0091] As a further alternative, the patient monitor may be directlyconnected to a hard-wired connection on physical data transportstructure 32 with an Ethernet or similar connection technology, asindicated at 208. As with a patient monitor that is connected tocommunicate using wireless communications, a patient monitor directlyconnected to physical data transport structure 32 may have a permanentlyassigned IP address, or may request the assignment of an IP address oncethe physical connection is established. In any event, in the hard-wiredimplementation, the terminal server is then prepared to initiate arequest for communications to one or more central stations.

[0092] Regardless of how a patient monitor establishes a connection withphysical data transport structure 32, the patient monitor must thenestablish communications with a central station by broadcasting arequest for communications to the central station, as indicated at 210.It will be appreciated by those of skill in the art that a patientmonitor may broadcast a request for communications in any of a varietyof ways. In the exemplary embodiment, the patient monitor transmits therequest as a UDP broadcast to all central stations. Alternatively, othercommunication protocols may be used.

[0093] The UDP communications request may include a variety ofparameters adapted to inform the central station about the patientmonitor. For example, communications requests typically include suchinformation as the identity, type, and/or capabilities of the patientmonitor, the IP and MAC (Media Access Control) addresses of the patientmonitor, the version of software installed on the patient monitor, etc.The request may also include an indicator of the type of communicationsdesired. For example, the patient monitor may request communications toestablish central monitoring of a patient, download newer versions ofthe patient monitoring software (discussed in more detail below), orperform network maintenance, etc. This information allows the centralstation to determine how to respond to the request. Unless statedotherwise, the description below will assume that the patient monitor'scommunications request is for the purposes of establishing centralizedmonitoring of a patient.

[0094] In the exemplary embodiment, the communications request is passedto, and received by, all central stations of network 30, as indicated at212. Any routers or other network devices connected to physical datatransport structure 32 are configured to pass on the request to thecentral stations as necessary. Alternatively, the request may beconveyed to fewer than all of the central stations, or to a singlecentral station. Each central station is configured to respond to thecommunications request when received. Upon receiving the first responsethe patient monitor transmits an acknowledgement to the central stationthat sent the first response. The patient monitor is configured toreject subsequent responses by transmitting a “reject” message to anycentral station that sends a subsequent response. The central stationsare configured to cease sending responses to the communications requestafter receiving a “reject” message, unless a new request forcommunications is received.

[0095] In some embodiments, the central stations may be configured toensure that a preferred central station responds to the communicationsrequest. For example, the central stations may be configured torecognize a patient monitor that has communicated with network 30 in thepast (e.g., based upon information transmitted in the communicationsrequest), and to allow the particular central station that waspreviously in communication with the patient monitor to respond first.Thus, in the exemplary embodiment the central stations are configured todetermine if a communications request was sent by a patient monitorwhich was previously in communication with a particular central stationwithin a predefined time period. If so, the particular central stationis configured to respond to the request immediately, while the remainingcentral stations will wait for a relatively short period of time (e.g.,10, 15, 20, 25, or 30 seconds, etc.) before responding. This priority isbased on the assumption that the patient monitor is likely stillconnected to the same patient as during the previous communications, andthat the patient is likely to be monitored at the same central stationas during the previous communications. In any event, once the patientmonitor receives a first response to its communications request, thepatient monitor and the central station which sent the first response(hereinafter referred to as the “provisional central station”) begincommunicating to configure the centralized monitoring session, asindicated at 214.

[0096] As will be described in more detail below, the particular centralstation which serves as the provisional central station begins theprocess of configuring the monitoring session. However, before thecentralized monitoring begins, one of the central stations of network 30is selected to complete the configuration process and perform thecentral monitoring. This selected central station is referred to hereinas the “primary central station.” If the provisional central station isselected to be the primary central station, then no change incommunications is needed, and the provisional central station assumesthe role of the primary central station. Conversely, if a differentcentral station is selected to be the primary central station,communications with the patient monitor are transferred from theprovisional central station to the selected central station, which thenassumes the role of primary central station.

[0097] As is known to those of skill in the art, wireless communicationswhich have been established between a patient monitor and a primarycentral station may be lost or “dropped” for any of a variety ofreasons. For example, the wireless transmissions may not be received bythe access point and/or the wireless transceiver of the patient monitorbecause the patient monitor is moved out of the defined range of network30 (i.e., out of range of any access point). Similarly, thetransmissions may have been blocked by structures between the patientmonitor and the access point, such as when the patient monitor is takeninto an elevator or similar enclosure. Alternatively, a portion ordevice of network 30 may have failed, causing the communications to bedropped. As a further alternative, the battery in the patient monitormay have been replaced or discharged, causing the patient monitor tolose communications.

[0098] The response by patient monitor 22 and central stations 24 tocommunications dropouts may vary depending on the length and/or cause ofthe dropout. In the exemplary embodiment for example, a relatively briefdropout (e.g., less than approximately 10, 20, or 30 seconds, etc.), istreated as an interruption rather than as an actual loss ofcommunications. Lost or incomplete transmissions due to suchinterruptions may be resent, discarded, or ignored according to thecommunications protocols used by the patient monitor and centralstations. Once the interruption ends, the patient monitor and primarycentral station resume communicating as before.

[0099] In the event of a loss of communications that extends beyond abrief interruption, exemplary patient monitor 22 is configured to detectthe loss and automatically attempt to restore the communications. If thepatient monitor is no longer associated with an access point, thepatient monitor attempts to establish an association as described in the802.11 standard, and continues to attempt to establish an associationuntil association with an access point is regained. Once the patientmonitor re-associates with an access point (or if the patient monitornever lost the association), the patient monitor broadcasts a requestfor communications to the central stations, and the rendezvous processproceeds as described above. Once the patient monitor is incommunication with a provisional central station, the patient monitorand provisional central station begin the process of configuring themonitoring session, as indicated at 214.

[0100] It will be appreciated that the session configuration process mayproceed in any of a variety of different ways to configure a variety ofdifferent monitoring parameters. For example, the configuration processmay identify which patient is being monitored, which central stationwill monitor the patient, which central station will control the patientmonitor, what types of vital signs data should be monitored, how thevital signs data should be analyzed, what alarm conditions should bedetected, how the patient monitor should function, etc. An exemplarysession configuration process is indicated generally at 216 in FIG. 12.During process 216 a primary central station is selected, the monitoredpatient is identified, and the patient's room or other location isspecified.

[0101] Referring to FIG. 12, the provisional central station firstdetermines whether the patient monitor is still connected to the samepatient as before the communications dropout. If such is the case, thenthe provisional central station assumes that the patient monitor isattempting to restore communications which were lost, and prior valuesfor patient identity, etc., may be used. Alternatively, if the requestis to establish new communications, then the central station determinesthe information needed to complete the configuration by querying a userof the patient monitor, as will be described in more detail below.

[0102] The provisional central station may be configured to employ avariety of different methods or mechanisms to determine whether thepatient monitor is still connected to the same patient. In the exemplaryembodiment for example, the provisional central station first sends arequest to the patient monitor for an indication of whether the patientmonitor was continuously monitoring the patient during the period thecommunications were lost, as indicated at 218. If the patient monitorresponds affirmatively, then the patient currently being monitored isnecessarily the same patient that was previously monitored.

[0103] Patient monitor 22 is configured to receive the request anddetect whether it continuously monitored the same patient during thecommunication dropout. Typically, the patient monitor is configured todetect continuous monitoring by detecting whether the patient monitorwas operational during the communications dropout, and whether vitalsigns data was continuously received via at least one of the sensorassemblies. For example, one exemplary ECG sensor assembly connectableto a patient is adapted to continuously send ECG vital signs data topatient monitor controller 100. If the patient monitor is disconnectedfrom the patient during the dropout, the ECG signal will lapse. Anylapse in the ECG vital signs data is detected by the controller.Alternatively, the ECG sensor assembly, or other types of sensorassemblies, may be configured to detect actual contact with the patient.In any event, the patient monitor responds to the request by informingthe provisional central station of whether the patient monitor hascontinuously monitored the same patient. It should be noted that thepatient monitor may be monitoring the patient through sensor assembliesthat do not continuously send vital signs data to the controller, andthat do not detect contact with the patient. In which case, the patientmonitor will be unable to confirm that it has continuously monitored thesame patient, and will respond to the request from the central stationaccordingly.

[0104] If, at step 218, the patient monitor responds that it hascontinuously monitored the same patient, the provisional central stationproceeds to perform a reconnect process, as indicated at 220 and asdescribed below. Alternatively, if the patient monitor responds that ithas not continuously monitored the same patient, the provisional centralstation then determines whether the patient monitor was recentlyconnected to network 30, as indicated at 222. In other words, if thetime period during which communications between the patient monitor andthe primary central station were lost is less than a predeterminedlength of time, then the provisional central station concludes that thepatient monitor is attempting to restore a recent connection, andproceeds to perform reconnect process 220. Otherwise, the provisionalmonitor concludes that the patient monitor is attempting to establish anew communications session. It should be noted that if the patientmonitor was continuously monitoring the same patient during thecommunications dropout, then the provisional central station may safelyassume the patient monitor is still connected to the same patientregardless of the length of the dropout.

[0105] The predetermined length of time that defines a recent connectionmay be set to any desired length of time as appropriate for a particularapplication. In the exemplary embodiment, the predetermined length oftime is selected to be less than the minimum time period (e.g., 1, 2, 3,4, or 5 minutes, etc.) normally needed to disconnect a patient monitorfrom one patient and reconnect the patient monitor to another patient.Thus, if the patient monitor was out of communication for any period oftime less than that minimum disconnection/reconnection time, theprovisional central station concludes that the patient monitor is stillconnected to the same patient. Alternatively, other time periods may beused.

[0106] The provisional central station may determine whether the patientmonitor was recently connected in various ways. Typically, each centralstation is adapted to store patient vital signs data in database system40. The vital signs data includes the time of collection by the patientmonitor and/or receipt by the central station. Thus, the provisionalcentral station may be configured to access database system 40 todetermine the time that the last vital signs data was received from thepatient monitor. Alternatively, the patient monitor may be configured todetermine the length of the dropout and to inform the provisionalcentral station, either automatically or in response to a query from theprovisional central station.

[0107] In addition to the length of time during which communicationswere lost, the provisional central station may be configured also toevaluate other conditions at step 222. For example, if the priorcommunications were dropped intentionally, i.e., in response to acommand by a user, the provisional central station may be configured toassume that a new patient has been connected to the patient monitor. Inwhich case, the patient monitor is not attempting to restore a recentconnection, but instead is attempting to establish a new communicationsconnection.

[0108] As mentioned above, the provisional central station proceeds toperform a reconnect process, indicated at 220, if the provisionalcentral station determines either that the patient monitor continuouslymonitored the same patient during the dropout, or that the patientmonitor was recently connected to communicate with a primary centralstation. During reconnect process 220 the provisional central stationautomatically determines which patient is being monitored by the patientmonitor, and which central station served as the primary central stationbefore the communications dropout. Typically, this information is storedby the patient monitor in memory device 102, and is communicated to theprovisional central station by the patient monitor. Alternatively, theinformation may be stored in database system 40 and read by theprovisional central station via physical data transport structure 32.

[0109] In any event, if the provisional central station is not theprimary central station, then the provisional central station conveys amessage to the primary central station to take over the remainder of therendezvous process. If the primary central station is available, itbegins communicating with the patient monitor via physical datatransport structure 32 and conducts the remainder of the configurationprocess as described below. Likewise, the patient monitor transmits allsubsequent communications to the primary central station, and theprovisional central station ends further communications with the patientmonitor.

[0110] Alternatively, if the primary central station does not respond tothe provisional central station or is otherwise unavailable, theprovisional central station may be configured to transmit a message tothe patient monitor that the primary central station is unavailable. Inthe exemplary embodiment, the patient monitor controller causes displayscreen 84 to display a user-interface 114, such as shown in FIG. 13,including a message that the primary central station is unavailable. Theuser-interface may also include instruction elements 116 which areselectable by a user to instruct the central station to recheck theavailability of the primary central station, or to try a new primarycentral station. The clinician or other user of the patient monitor mayuse buttons 86 to select the desired instruction, which the patientmonitor then communicates to the provisional central station. Dependingon the user's instructions, the provisional central station either sendsanother message to the primary central station to take over thecommunications, or transmits a list of central stations to the patientmonitor. In the latter case, controller 100 causes the display device todisplay a list of central stations, from which the user may select usingbuttons 86. The patient monitor transmits the user's selection to theprovisional central station, which sends a message to the selectedcentral station to take over the communications. If the selected centralstation is not available, the provisional central station informs thepatient monitor and the user either selects a different central station,or instructs the provisional central station to retry the selectedcentral station. This process may be repeated until an available centralstation is selected to act as the primary central station. The selectedcentral station then begins communicating with the patient monitor andconducts the remainder of the configuration process.

[0111] Once the primary central station takes over the communicationswith the patient monitor, the primary central station is configured todetermine the patient identity (patient ID) of the particular patientbeing monitored by the patient monitor. The primary central stationdetermines the patient ID by transmitting a request for the patient IDto the patient monitor. If the patient monitor cannot provide thepatient ID, the primary central station then accesses database system 40to obtain the patient ID which was stored during the patient monitor'slast communication session. Once the primary central station determinesthe identification of the particular patient being monitored by thepatient monitor, the primary central station thereafter associates allvital signs data received from the patient monitor with the particularpatient. In addition, the vital signs data along with other patientinformation may be stored on database system 40, and then retrieved forviewing and analysis at a later time.

[0112] After the primary central station has assumed the communicationswith the patient monitor and determined the identity of the patientbeing monitored, the primary central station then determines whether thepatient has been assigned to a particular location, such as a roomnumber, bed, ward, floor, etc., as indicated at 224 in FIG. 12. Thisinformation may then be displayed on central station monitor 36 toinform the clinician of the patient's assigned location. However, inview of the portability of patient monitors 22, a particular patient maybe temporarily absent from his or her assigned location even though thepatient is continuously monitored at the central station. In any event,the primary central station determines whether the patient has beenassigned to a particular location by sending a request for theinformation to the patient monitor. If the patient monitor is unable toprovide an assigned location, the primary central station may beconfigured to search database system 40 for the information.

[0113] If the primary central station is unable to determine theassigned location, the central station is configured to query the userof the patient monitor for the patient's assigned location, as will bedescribed in more detail below. Otherwise, the rendezvous andconfiguration processes are complete, and the primary central stationproceeds to confirm that no other patient monitor is monitoring the samepatient, as indicated at 226. In addition to checking the other patientmonitors in communication with the primary central station, the primarycentral station also communicates with other central stations in network30 to ensure that the same patient is not being monitored by a differentcentral station. In the event the primary central station determinesthat another patient monitor is monitoring the same patient, an alarm orother indication may be displayed at the primary central station and/orthe patient monitor so that a different patient ID may be selected.

[0114] As described above, the patient monitor is adapted toautomatically attempt to restore communications with its primary centralstation in the event the communications are lost. Upon reestablishingcommunication, the primary central station (or a provisional centralstation, if different than the primary central station) is configured toautomatically determine whether the patient monitor is still connectedto the same patient. The central station may use a variety of mechanismsand methods to determine whether the patient monitor is still connectedto the same patient, including measuring the length of time of thecommunications dropout, and determining whether the patient monitordisconnected from the patient data during the dropout. If the patientmonitor is still connected to the same patient, the central station thenassociates the patient monitor with the patient so that any vital signsdata received from the patient monitor is also associated with thepatient. It will be appreciated that the capability to automaticallyidentify the monitored patient at the central station after acommunications dropout, enables the central station to monitor a largenumber of patients without constant intervention by a clinician toreconfigure a patient monitor each time a dropout occurs. Furthermore,the automatic configuration ensures that centralized monitoring of thepatient resumes as soon as the patient monitor restores communicationwith the central station.

[0115] Turning attention back to FIG. 12, if the provisional centralstation determines that the patient monitor is not attempting to restorelost communications, the provisional central station proceeds toconfigure a new monitoring session by determining the identity of thepatient being monitored, the primary central station which will monitorthe patient, and the patient's assigned location. When the patientmonitor establishes a new communications connection with the provisionalcentral station, the patient monitor automatically displays anotification to a user of the patient monitor on display screen 84. Aswill be described below, the notification typically includes auser-interface operable by a user of the patient monitor to configurethe communications session.

[0116] It will be appreciated that the provisional central station maydetermine the identity of the monitored patient in various ways. Forexample, even where the patient monitor has not recently been incommunication with a central station and has not been monitoring thepatient continuously since its last communication with a centralstation, it nevertheless may be more likely than not that the patientmonitor has been reconnected to monitor the same patient. In theexemplary embodiment therefore, the provisional central station firstdetermines whether the identity of the previous patient monitored by thepatient monitor is available, as indicated at 228.

[0117] To determine whether the patient ID of the previous patient isavailable, the provisional central station may be configured first toquery the patient monitor. Exemplary patient monitor 22 is configured tostore the ID of the previous patient in memory device 102, unless thepatient ID is cleared by the user. Thus, the exemplary provisionalcentral station transmits a request to the patient monitor for theprevious patient ID. If the previous patient ID is available at thepatient monitor, the patient monitor communicates the previous patientID to the provisional central station. Otherwise, the patient monitorresponds that no patient ID is available.

[0118] If the patient ID is not available at the patient monitor, theprovisional central station may be configured to search database system40 for the previous patient ID associated with the patient monitor.Alternatively, if the patient monitor is connected to physical datatransport structure 32 via a hard-wired connection, the provisionalcentral station may be configured to search the database system for theprevious patient ID associated with the particular location of thehard-wired connection. This strategy is based on the likelihood that thepatient who was previously in the room with the hard-wired connectionhas not been moved since the last communications session. In theexemplary embodiment, the provisional central station is configured tosearch for the patient ID associated with the patient monitor if thepatient monitor is communicating via wireless transmissions, and tosearch for the patient ID associated with the particular location of thehardwired connection if the patient monitor is communicating via wire.

[0119] If the previous patient ID is available (either from the patientmonitor or the database system), the provisional central stationcommunicates an instruction to the patient monitor to confirm whetherthe patient currently being monitored is the same as the last patientmonitored, as indicated at 230. In response, controller 100automatically causes display screen 84 to display a user-interface 114,such as illustrated in FIG. 14. The user-interface displays the previouspatient's identity (i.e., the patient's name, identifying number, and/orother identifying designation) and asks the user to confirm that thepatient monitor is connected to the previous patient. Exemplaryuser-interface 114 also includes instruction elements 116 which areselectable by the user to indicate that the patient monitor is or is notconnected to the previous patient. In the exemplary embodiment, theuser-interface also displays the patient's assigned location, indicatedat 118, and the central station that previously monitored the patient,indicated at 120. Thus, the clinician or other user is prompted byuser-interface 114 to confirm that the same patient is being monitored,and is assigned to the same location, and is to be monitored by the samecentral station. Alternatively, the user may indicate that a new patientis being monitored, or that the patient has been assigned to a newlocation, or that the patient should be monitored by a different centralstation. The user's selection is communicated by the patient monitor tothe provisional central station.

[0120] As shown in FIG. 12, if the user confirms the previous patient,location and primary central station (i.e., by selecting the instructionelement labeled “YES”), the rendezvous and configuration processes arecomplete, and the primary central station proceeds to confirm that noother patient monitor is monitoring the same patient, as indicated at226 and as discussed above. It should be noted that if the provisionalcentral station is not the primary central station, then the provisionalcentral station sends a request to the primary central station to takeover the communications and complete the configuration process, asdescribed above.

[0121] Alternatively, if the user responds by selecting a different oneof the instruction elements, the provisional central station proceeds todetermine the necessary configuration information. For example, if theuser indicates that the patient currently being monitored is not theprevious patient (i.e., by selecting the instruction element labeled“NO”), the provisional central station determines whether the patientmonitor is configured to display a list of patients, as indicated at232. The provisional central station may determine whether the patientmonitor is configured to display a list of patients in various ways,including by sending a query to the patient monitor for itscapabilities, or by accessing database system 40 to ascertain thecapabilities of the patient monitor based on the type of patientmonitor. As mentioned above, the type of the patient monitor may betransmitted to the provisional central station during the initialportion of the rendezvous process.

[0122] If the patient monitor is not configured to display a list ofpatients, then the patient ID confirmation process is passed to thecentral station, as indicated at 226. The central station typically isconfigured to display a user-interface allowing a clinician to specifythe patient ID and the patient's assigned location. In addition, theclinician may instruct the central station to transfer communicationswith the patient monitor to a different central station, as will bedescribed in more detail below. If, on the other hand, the patientmonitor is configured to display a list of patients, the central stationaccesses database system 40 to identify at least some of the patientsadmitted to the hospital, and transmits a list of those patients to thepatient monitor.

[0123] As indicated at 234, exemplary controller 100 displays the listof patients on display screen 84. An exemplary display screen presentinga list of patients is illustrated in FIG. 15. Rather than identifyingthe patient at the patient monitor, the clinician may operate buttons 86to instruct that the patient's ID be selected at the central station, asindicated at 236. In which case the patient ID confirmation process ispassed to the central station, as indicated at 226 and as discussedabove. Alternatively, the clinician may select the ID of themonitored-patient from the patient list. The patient's ID is thencommunicated to the central station by the patient monitor. Next, thecentral station transmits a list of locations to the patient monitorcontroller, which displays the list to the user, as indicated at 238.Once the user selects the patient's assigned location from the list, thecontroller communicates the information to the central station. Finally,the central station confirms the patient is not being monitored by adifferent patient monitor, as indicated at 226, at which point therendezvous and configuration processes are complete.

[0124] If, at step 230, the clinician indicates that the patient hasbeen assigned to a different location (i.e., by selecting theinstruction element labeled “NEW ROOM”), the patient monitorcommunicates this information to the central station, which responds bysending a list of locations to the patient monitor, as described above.The clinician then selects the patient's assigned location from thelist, as indicated at 238. The location assignment is communicated tothe central station, which then completes the rendezvous andconfiguration processes by confirming that the patient is not beingmonitored by a different patient monitor.

[0125] Returning attention briefly to FIG. 14, if the central stationthat monitored the previous patient will not be the primary centralstation, the clinician requests communications with a different centralstation (e.g., by selecting the control element labeled “NEW UNIT”). Theclinician's instruction is then communicated to the provisional centralstation, which responds by transmitting a list of central stations innetwork 30. Controller 100 displays the list of central stations ondisplay screen 84, as indicated at 240 in FIG. 12. FIG. 16 illustratesan exemplary user-interface on display screen 84, including a list ofuser-selectable central stations. Once the clinician selects the desiredcentral station from the list, the selection is communicated to theprovisional central station. If the provisional central station is notthe selected central station, the provisional central station sends arequest to the selected central station to take over the communicationsand configuration process. If the selected central station is available,it takes over the communications with the patient monitor and completesthe configuration process. Otherwise, the provisional central stationcauses the patient monitor to notify the clinician that the selectedcentral station is unavailable, as described above.

[0126] Once the a central station is selected to be the primary centralstation and assumes the communications with the patient monitor, theprimary central station proceeds to determine the identity of thepatient and the patient's assigned location. As described above, theidentity of the patient and the patient's assigned location may beentered by the clinician at the patient monitor and then communicated tothe primary central station. Alternatively, the patient ID and assignedlocation may be specified at the primary central station. In any event,once the primary central station has confirmed the identity and theassigned location of the patient, as indicated at 226, the rendezvousand configuration processes are complete.

[0127] As described above, exemplary configuration process 216 isadapted to automatically determine the patient's identity, etc.,whenever possible. This tends to minimize the amount of effort requiredby the clinician to configure the patient monitor for centralizedmonitoring. However, it will be appreciated that the provisional centralstation may be configured also to determine the patient identity,primary central station, and assigned location in other ways. Forexample, if the patient ID is not available at step 228, then theexemplary provisional central station is configured to determine whethera list of central stations should be presented to the clinician, asindicated at 232. Typically, a list of central stations is presentedwhenever network 30 includes more than one central station. As indicatedat 240 and described above, the provisional central station transmitsthe list of central stations to the patient monitor for display to theclinician. The clinician selects a desired central station to serve asthe primary central station. The patient monitor communicates theselection to the provisional central station, which sends a message tothe selected central station to take over the communications. If theselected central station is not available, the clinician is informed tomake another selection, as described above. If, at step 242, theprovisional central station determines that a list of central stationsshould not be presented to the user, the provisional central stationbecomes the primary central station and completes the remainder of theconfiguration process.

[0128] Once the primary central station is in communication with thepatient monitor, the primary central station queries the clinician forthe patient ID and assigned location. Alternatively, the patient ID andassigned location may be specified at the primary central station. Inany event, the primary central station then confirms that no otherpatient monitors are monitoring the same patient, thereby completing therendezvous and configuration processes.

[0129] It will be appreciated by those of skill in the art that theexemplary rendezvous and configuration processes illustrated in FIGS. 11and 12 and described above, provide a variety of capabilities formonitoring patients via medical telemetry network 30. For example, aclinician may select which central station will monitor the patient byentering instructions at the patient monitor. The clinician'sinstructions are communicated to the provisional central station, whichthen sends a request to the selected central station to take over thecommunications. Alternatively, the patient monitor may send a requestfor communications directly to the selected central station in responseto the clinician's instructions. In any event, the clinician is notrequired to configure the patient monitor at the central station, butinstead may configure and initiate the central monitoring processwithout leaving the patient's location.

[0130] Furthermore, exemplary patient monitor 22 is configured toautomatically attempt to establish communications with a central stationbeginning at power-up. The patient monitor determines, without userintervention, the communications settings needed to establish aconnection and to communicate with network 30 such as transmissionfrequency, IP addresses, synchronization, etc. Thus, a patient monitormay be shipped from its manufacturing site to any location in the worldand the patient monitor will automatically configure itself to begincommunications with a local medical telemetry network according to thepresent invention. Similarly, a patient monitor used in a network at onelocation may be taken to a different location, where the patient monitorwill configure itself to communicate with the local medical telemetrynetwork at the different location. As a result, patient monitors 22 maybe operated without specialized training or knowledge in networkcommunications. Instead, clinicians may place a new patient monitor inimmediate use simply by powering-up the patient monitor.

[0131] If communications between a patient monitor and central stationare lost, the patient monitor automatically attempts to restore thecommunications without requiring reconfiguration. However, if thepatient monitor is attempting to establish a new communicationsconnection, the clinician or other user of the patient monitor isautomatically notified once a communications connection (either wire orwireless) is established to allow the monitoring session to beconfigured. A user-interface for configuring the monitoring session isautomatically displayed on the patient monitor display screen. Theuser-interface is at least partially defined by instructions receivedfrom the central station, and is operable by a user of the patientmonitor to identify the monitored patient, and to select a primarycentral station to perform the central monitoring, etc. After a primarycentral station is identified and assumes communications with, andcontrol of, the patient monitor, the patient is continuously monitoredat the primary central station. In view of the capability of the patientmonitors and central stations to automatically initiate and configurethe centralized monitoring process, system 20 represents a substantialadvancement in patient monitoring.

[0132] It will be appreciated by those of skill in the art that therendezvous and configuration processes described above are just one ofthe many ways in which the central stations and patient monitors may beconfigured to establish new communications and/or restore lostcommunications. Many variations and modifications to the rendezvous andconfiguration processes are possible within the scope of the invention.Therefore, it will be understood that the invention is not limited tothe particular exemplary processes described above, but includes allsuch processes, variations, and modifications suitable for establishingcommunications between a patient monitor and a central monitoringstation via a communications network structure.

[0133] Once patient monitor 22 has established (or restored)communications with the primary central station, the patient monitor isconfigured to continuously communicate the vital signs data it collectsto the central station. In the exemplary embodiment, patient monitor 22is configured to communicate all vital signs data that is collected.Alternatively, the patient monitor may be configured to communicate onlya portion of the vital signs data collected. In any event, the centralstation is configured to receive the vital signs data and associate itwith the patient being monitored. As mentioned above, the centralstation typically is configured to communicate simultaneously with aplurality of patient monitors, in which case the vital signs datareceived from each patient monitor is associated with the particularpatient connected to that patient monitor.

[0134] Although patient monitor 22 is adapted to communicate with one ormore central stations to establish central monitoring, the patientmonitor is also configured to provide patient monitoring at thepatient's location. As mentioned above, exemplary controller 100 isadapted to receive the vital signs data via sensor ports 82, and todisplay an image on display screen 84 that represents at least a portionof the vital signs data. It will be appreciated that the image may takeany of a variety of different forms which will vary depending on thetype of vital signs data collected. Thus, exemplary patient monitor 22provides continuous local monitoring regardless of whether the patientmonitor is in communication with a central station. Buttons 86 enable aclinician or other user to control a variety of functions including theinformation displayed on display screen 84, the format of the displayedimage, the vital signs data collected, analysis of the vital signs data,alarm conditions, etc. For example, controller 100 may be controllableto display signals from selected sensor assemblies such as an ECG sensorassembly, or from a selected electrode of the ECG sensor assembly. Inaddition, the controller may be configured to analyze at least some ofthe collected vital signs data using one or more user-selectableparameters to provide additional information.

[0135] Similarly, controller 100 may be configured to analyze the vitalsigns data to detect whether the data is within certain defined nominalranges, and to indicate an alarm condition if the controller detectsthat a portion of the data is not within the defined ranges. Forexample, if the upper and lower parameter values for heart rate are 120and 50 beats per minute, respectively, the patient monitor will indicatean alarm if the detected heart rate is either greater than 120 or lessthan 50 beats per minute. Alternatively, any other portion of thecollected vital signs data may be analyzed for alarm conditions, such asblood pressure, temperature, oxygen saturation in the patient's blood(SpO2), etc. Further, the defined nominal ranges typically are variableparameters and selectable by the user to specify particular alarmconditions for a particular patient. FIG. 17 illustrates an exemplaryuser-interface displayable on display screen 84, and operable by aclinician to specify the parameter values used by controller 100 toanalyze the vital signs data. Alarm indications may include warningmessages on display screen 84 and/or warning sounds from audio outputdevice 92, etc.

[0136] Patient monitor 22 may also be configured to detect equipment orcommunications problems and provide an indication of the problem to theuser. For example, controller 100 may be configured to detect a lowpower level in battery assembly 88, a sensor assembly that has becomedisconnected from the patient, a malfunction in buttons 86, lostcommunications, etc. The indication provided to the user may be the sameas or different than the indication provided in response to the alarmconditions.

[0137] When patient monitor 22 is in communication with network 30, theprimary central station may be configured to control some or all of thefunctions of the patient monitor. This enables a clinician to control aplurality of remotely distributed patient monitors from a singlelocation. In addition, a central station may be configured to enable aclinician to control all patient monitors in communication with thecentral station to function identically. Alternatively, the clinicianmay control each patient monitor to function differently.

[0138] In the exemplary embodiment, the primary central station isconfigured and operable to change the variable parameter values whichdefine nominal data ranges. Thus, the clinician can set or change thedetection of alarm conditions at the primary central station.Instructions entered by the clinician at the primary central station arecommunicated to controller 100. The controller is configured to changethe specified variable value in response to the instruction, and toanalyze the vital signs data using the new value. Similarly, the primarycentral station may be configured to communicate instructions tocontroller 100 specifying what portions of the vital signs data shouldbe analyzed. For example, it is known to those of skill in the art thata patient's heart rate may be determined from ECG data or from SpO2data. Thus, where the patient monitor is collecting both ECG data andSpO2 data from a patient, a clinician at the central station may specifywhich type of data the controller analyzes to determine heart rate.

[0139] In addition, since the central stations typically have greaterdata processing capability than the patient monitors, the primarycentral station may be configured to analyze the vital signs datareceived from the patient monitor to determine additional information.For example, the primary central station may be configured to perform STand/or arrhythmia analysis on the ECG waveform data, whereas controller100 may analyze the ECG waveform to determine only the patient's heartrate. If the primary central station detects an alarm condition as aresult of the analysis, the alarm condition may be displayed on centralstation monitor 36. In addition, the primary central station maycommunicate the alarm condition to the patient monitor and instructcontroller 100 to present an indication of the alarm condition at thepatient monitor. By varying where the vital signs data analysis occurs(at the central station or at the patient monitor), the patientmonitor's resources may be concentrated on collecting the vital signsdata and presenting information to a clinician attending the patient.

[0140] The primary central station may also be configured to controlboth the types of information and the image displayed on display screen84. For example, where the ECG sensor assembly includes a plurality ofelectrodes, the clinician at the primary central station may instructthe patient monitor to display the waveform from a particular one of theelectrodes, as shown in FIG. 18. Alternatively, the clinician mayinstruct the patient monitor to display the waveforms from a pluralityof the electrodes, as shown in FIG. 19. It will be appreciated thatcontroller 100 may be configured to control display screen 84 to displayany desired information or image format in response to instructionsreceived from the primary central station. Alternatively, the controllermay be configured to turn off a portion or all of the display screen inresponse to instructions from the central station.

[0141] As described above, the patient monitor and/or the primarycentral station may be configured to indicate an alarm condition,equipment problem, etc., with at least one of a visible indicator or anaudible indicator. For example, FIG. 20 illustrates an exemplary imagedisplayable on display screen 84 which indicates an alarm condition.Typically, the user-interface will include an icon or other indicia tospecify the cause of the alarm or problem (e.g., high heart rate, hightemperature, etc.).

[0142] The patient monitor and primary central station may be configuredto continue presenting the indicator for a predetermined time period, orfor as long as the condition or problem persists. Alternatively, theindicator may be terminated after a specified period of time, even ifthe condition or problem has not ended. In the exemplary embodiment, theindicator also may be terminated (or suspended for a defined timeperiod) if the clinician acknowledges the indication at the patientmonitor and/or the primary central station. Thus, an alarm conditiondetected at the primary central station and communicated to the patientmonitor may be acknowledged at the patient monitor. The acknowledgementis communicated to the primary central station, which then terminatesthe indication. As a result, a clinician attending the patient need notleave the patient's location to return to the primary central stationand acknowledge the alarm.

[0143] Once communications are established between a patient monitor anda primary central station of the exemplary embodiment, the patientmonitor communicates all vital signs data to the primary central stationand is controlled by the primary central station. While other centralstations also may receive the vital signs data and send instructions forthe patient monitor (as will be described in more detail below), theprimary central station maintains control of the patient monitor and isresponsible for providing the central monitoring. However, control andcentral monitoring of the patient monitor may be transferred to adifferent central station, in which case the different central stationis configured to take over communications with the patient monitor andassume control of the central station.

[0144] In the exemplary embodiment, a clinician may transfer control ofthe patient monitor to a different central station by entering atransfer instruction at the patient monitor or at the primary centralstation. If the clinician is at the patient monitor, controller 100transmits the transfer instruction to the primary central station, whichresponds by sending a list of central stations to the patient monitor.The controller displays the list on display screen 84 to allow theclinician to select the desired central station. Once the clinicianmakes a selection, the patient monitor communicates the selection to theprimary central station, which sends a request to the selected centralstation to take over the communications. If the selected central stationis unavailable, the primary central station sends a notification to thepatient monitor so that the clinician can make another selection.Alternatively, the patient monitor may communicate with the selectedcentral station directly. However, if the clinician is at the primarycentral station when transferring control, the primary central stationsends a request to the selected central station to take over thecommunications, as described above. Once the selected central stationtakes over as the new primary central station, the patient monitorcommunicates all subsequent vital signs data to the new primary centralstation.

[0145] As mentioned above, communications dropouts between the patientmonitor and the primary central station may occur for a variety ofreasons. Once a dropout occurs, the patient monitor begins attempting torestore the communications. However, during the dropout, the patient isnot monitored at the central station. Therefore, the patient monitor maybe configured to detect when central monitoring has ended, and to takeadditional steps to minimize any disruption due to the dropout.

[0146] In the exemplary embodiment, the patient monitor is configured tofunction differently when out of communication with a central station.For example, controller 100 may disable buttons 86 (e.g., bydisregarding inputs at the buttons) when the controller is incommunication with a central station so that the functions of thepatient monitor can only be changed at the central station.Alternatively, the controller may suppress alarm indications at thepatient monitor when in communication with a central station. Similarly,the controller may turn off the display when in communication with acentral station to conserve battery power. The controller may beconfigured to perform the above steps either automatically, or inresponse to an instruction from the central station. However, thecontroller typically is configured to activate the buttons, the displayand the alarm indications when not in communication with a centralstation.

[0147] Furthermore, some embodiments of patient monitor 22 include abutton 86 operable by the patient to request clincian assistance (i.e.,a “Nurse Call” button). In such case, the patient monitor may beconfigured to respond differently to activation of the button dependingon whether the patient monitor is in communication with a centralstation. For example, the patient monitor may be configured to sound anaudible alarm if the patient monitor is not in communication with acentral station, or to forward the request for assistance to a centralstation without sounding an audible alarm if the patient monitor is incommunication with a central station.

[0148] Similarly, when communications between the patient monitor andcentral station are lost, the patient monitor may be configured toautomatically switch from a centrally-monitored mode, in which the vitalsigns data is communicated to a central station that at least partiallycontrols the patient monitor, to a stand-alone mode, in which the vitalsigns data are not communicated to a central station. Typically, thepatient monitor also is configured to automatically switch from thestand-alone mode to the centrally-monitored mode when the communicationsare restored. In other words, the patient monitor may be configured toautomatically relinquish at least partial control of the patientmonitoring process when in communication with a central station, but toresume full control in the event communications are lost.

[0149] In addition to automatically switching between a stand-alone modeand a centrally-monitored mode, the patient monitor may also beconfigured to take any one or more of a variety of steps to return tothe centrally-monitored mode with minimal disruption. As described abovefor example, the exemplary patient monitor is configured toautomatically and continuously attempt to restore the communicationsduring the dropout. Upon restoring a connection to physical datatransport structure 32, the patient monitor is configured to reestablishcommunications with a primary central station and, where possible, toconfigure the monitoring session without intervention by a clinician.

[0150] Nevertheless, the vital signs data are not communicated to thecentral station during the dropout. As a result, further analysis at thecentral station of the vital signs data received during the dropoutcannot be conducted, and the vital signs data cannot be stored ondatabase system 40 for later access. Therefore, exemplary patientmonitor 22 could be configured to store at least a portion of the vitalsigns data collected during the dropout, and then communicate the storedvital signs data to the central station once the communications arerestored. The vital signs data may be stored in memory device 102 and/orsome other data storage buffer. In any event, the data collected duringa dropout period would not be lost.

[0151] It will be appreciated that, depending on the length of thedropout, the vital signs data collected may exceed the patient monitor'sstorage capacity. Therefore, the patient monitor may be configured tostore only a portion of the vital signs data collected once it detectsthe dropout. For example, the patient monitor may be configured to beginstoring the data immediately after detecting the dropout, and then ceasestoring new data once the memory device is full. Alternatively, thepatient monitor may be configured to begin storing the data immediately,and once the memory storage is full, to begin storing subsequent data inplace of the oldest stored data. As a further alternative, the patientmonitor may be configured to store only data from selected sensorassemblies rather than all sensor assemblies.

[0152] As another alternative, the patient monitor may be configured tostore portions of the vital signs data which meet defined criteria. Inthe exemplary embodiment for example, controller 100 is configured toanalyze the vital signs data received during a dropout, and to detectthe occurrence of a medically-significant event based on the vital signsdata. The controller only stores data that corresponds to the occurrenceof a medically-significant event. Examples of typicalmedically-significant events include alarm conditions, arrhythmia,activation of the Nurse-Call button, etc. The amount of data stored mayvary depending on the event. Typically, a continuous sequence of data isstored from a point in time several seconds or minutes before the eventis detected to several seconds or minutes after the event ends. Thus,several running seconds or minutes of prior data are continuouslybuffered until an event is detected, at which point all or a portion ofthe data is stored until the event ends.

[0153] It will be appreciated that the criteria defining amedically-significant event may vary depending on the type of event, thetype of sensor assembly that collects the data, the condition of thepatient, the clinician's judgment, etc. The patient monitor may bepre-programmed with the criteria defining medically-significant events.Alternatively, the criteria for medically-significant events may beprogrammed into the patient monitor by the clinician or received fromthe central station. In any event, by storing only data corresponding tothe occurrence of medically-significant events, the patient monitor isable to conserve data storage capacity while ensuring that communicationdropouts do not prevent the primary central station from receiving themost important vital signs data.

[0154] Alternatively, or additionally, exemplary patient monitor 22 maybe configured to selectively store data under other conditions. Forexample, controller 100 may store data at selected time intervals, or inresponse to an instruction from a clinician via buttons 86, etc. Thus,it will be appreciated that the patient monitor may be configured toselectively store data under any conditions as desired for a particularapplication.

[0155] In the embodiments described above, patient monitor 22communicates collected vital signs data to a single central station,referred to herein as the primary central station. Likewise, the patientmonitor is controlled by the primary central station. However, in otherembodiments, the patient monitor may be configured to broadcast thevital signs data it collects to a plurality of central stations, and toreceive and execute instructions from a plurality of central stations.As a farther alternative, the primary central station may be configuredto convey vital signs data received from a patient monitor to one ormore other central stations.

[0156] As shown in FIG. 21, exemplary primary central station 24 a isconfigured to receive vital signs data from patient monitor 22, and toforward the vital signs data to one or more secondary central stations24 b. The vital signs data received from the patient monitor may then bedisplayed at the secondary central station(s) as well as at the primarycentral station. Typically, the secondary central station communicates arequest to the primary central station to receive a particular patient'svital signs data. In response to the request, the primary centralstation is configured to continuously forward all vital signs data itreceives that is associated with the particular patient. In addition,instructions entered at a secondary central station are communicated tothe primary central station, which forwards the instructions to thepatient monitor for execution. Thus, from the point of view of aclinician monitoring the patient, a secondary central station providesthe same capabilities as the primary central station. However, somefunctions are performed only at the primary central station, such asstoring or archiving the vital signs data to database system 40,performing arrhythmia analysis, etc.

[0157] It will be appreciated that communicating the vital signs data toone or more secondary central stations allows the patient's data to bemonitored by clinicians at plural locations within the hospital. Thus,there is no need for a clinician to travel to a different floor, or careunit, etc., of the hospital to view the data from a particular patient.Similarly, a clinician endeavoring to monitor a particular patient isnot restricted to a single location, but instead can monitor the patientfrom a variety of different locations.

[0158] In addition to providing central monitoring from multiplelocations, secondary central stations 24 b may also be configured toprovide a failsafe in the event of a failure involving the primarycentral station. Thus, in the exemplary embodiment, at least one of thesecondary central stations is configured to automatically attempt totake over communications with the patient monitor if communicationsbetween primary central station 24 a and the patient monitor are lost.The secondary central station may be configured to detect the loss ofcommunications from the primary central station in a variety of ways. Inthe exemplary embodiment, the secondary central station is configured todetect a loss of communications with the primary central station(even asudden, catastrophic one such as loss of power). In response to themessage, the secondary central station would then attempt to establishcommunications with the patient monitor. Additionally, the secondarycentral station is configured to monitor the communications it receivesfrom the primary central station, and if the primary central stationsuddenly stops communicating (e.g., due to loss of power, malfunction,etc.) for a defined period of time, the secondary central station isconfigured to attempt to establish communications with the patientmonitor. Alternatively, the patient monitor may be configured totransmit a request for communications to the secondary central stationin the event the primary central station stops communicating.

[0159] Once the secondary central station establishes communicationswith the patient monitor, the secondary central station takes over thefunctions of the primary central station. Alternatively, the clinicianmay be prompted to select a new primary central station for furthermonitoring. Where plural secondary central stations are monitoring thepatient monitor, the first secondary central station to establishcommunications with the patient monitor takes over as the primarycentral station. The new primary central station then begins forwardingthe vital signs data received from the patient monitor to the remainingsecondary central stations. Thus, the patient continues to be monitoredat a central location staffed by clinicians, and the vital signs datacollected from the patient continues to be stored for later retrieval.

[0160] As described above, patient monitor 22 and central stations 24are configured to automatically establish and maintain communicationswhile the patient monitor is monitoring a patient. However, patientmonitor 22 may also be operable to end the communications with thecentral station(s). This provides an intentional and controlledtermination of communications so that the patient monitor and/or thecentral stations do not automatically attempt to restore communications.In the exemplary embodiment, the patient monitor is operable by aclinician (e.g., using buttons 86) to transmit an end-communicationssignal to the primary central station. The primary central station isconfigured to send a confirmation of the end-communications signal tothe patient monitor, which is displayed to the clinician at the patientmonitor. The primary central station may also send a notification to thesecondary central stations, if any.

[0161] Once the end-communications signal has been received andconfirmed, the patient monitor may be powered down by the clinicianwithout causing the primary central station to report a loss ofcommunications. The primary central station will of course detect theloss of communication, but will be configured not to report this type ofloss because it is expected. Alternatively, the primary central stationwill terminate the communications after a defined delay period eventhough vital signs data were still being received. If the patientmonitor is still operating and collecting data after the communicationsare terminated, the patient monitor would be required to initiate therendezvous process described above to resume centralized monitoring ofthe patient. Any monitoring parameters, alarm conditions, etc., thatwere changed at the patient monitor in response to an instruction fromthe central station would be reset to the nominal default values storedby the patient monitor. Likewise, any monitoring parameters, alarmconditions, etc., that were changed at the central station in responseto an instruction from the clinician at the patient monitor, would bereset to the nominal default values stored by the central station.

[0162] As shown in FIGS. 1 and 2 and described above, patient monitor 22b is configured to establish communications with a central station andcommunicate vital signs data via either one of output port 96 orwireless transceiver 104 (illustrated in FIG. 7). In addition, exemplarypatient monitor 22 b is configured to detect whether output port 96 isconnected to physical data transport structure 32 (either directly orthrough terminal server 42), and to switch automatically betweenwireless communications and wire communications depending on whether theoutput port is connected to the network structure. For example, wherepatient monitor 22 b is initially in communications with a centralstation via output port 96 and the output port is disconnected fromphysical data transport structure 32, then controller 100 is configuredto automatically associate with an access point and continue thecommunications with the central station via wireless transceiver 104.Similarly, where patient monitor 22 b is in wireless communications witha central station when output port 96 is connected to physical datatransport structure 32, controller 100 is configured to automaticallycease communicating via wireless transceiver 104, and instead tocommunicate with the central station via the output port. Thus, theclinician can select whether patient monitor 22 b communicates usingwire or wireless communications by connecting and disconnecting,respectively, output port 96 to physical data transport structure 32.

[0163] As mentioned above, patient monitor 22 may also be configured toestablish communications with a central station to download newerversions of the control software stored in memory device 102 andexecutable by controller 100. It will be appreciated that the downloadprocess may be carried out in any of a variety of different ways withinthe scope of the invention. It should also be understood that thecontrol software could be for any component of the patient monitor, suchas by way of examples, computer cards associated with any/all of thesensor assemblies (e.g. a pulse oximetry card, an NIBP card, etc.),computer cards associated with radio telemetry, etc.

[0164] In the exemplary embodiment, patient monitor 22 is operable by auser to request a software update. In response to the user'sinstructions, the patient monitor attempts to establish communicationswith one or more central stations, and transmits a query for newversions of the software to the central stations. The query is includedas a part of the request for communications which the patient monitorbroadcasts to the central stations during the rendezvous process. Eachcentral station responding to the request indicates the version of thesoftware stored at the central station. The patient monitor waits adefined period (e.g., 10 seconds) to receive responses from the centralstations, and then selects a central station with the newest version ofthe software. Thus, even where the central stations have multipleversions of the software, the patient monitor is configured to determinewhich central station(s) has the newest version and to download thesoftware from the central station with the newest version. This allows asystem administrator to store new versions of the software on just oneor a few of the central stations, and then operate the patient monitorsto automatically find and download the newest software.

[0165] Once a central station with the newest version of the software isselected, the patient monitor transmits a request to the selectedcentral station to download the new software. The selected centralstation responds by transmitting the new software via either wire orwireless communications, depending on whether the patient monitor iscommunicating via output port 96 or wireless transceiver 104. Thesoftware download may be carried out using any of a variety of methodsor protocols, such as Trivial File Transfer Protocol (TFTP), etc.Typically, the patient monitor and selected central station verify thatthe software was accurately received at the patient monitor using one ormore of a variety of error-checking methods known to those of skill inthe art. Once the patient monitor receives the new software, controller100 updates the control software by installing the new software. Thecontroller may carry out this updating process for control software ofany of components of the patient monitor as described above.

[0166] As described above, the invention provides a system forcontinuously monitoring a plurality of patients at one or more centralstations using a plurality of portable patient monitors. The inventionalso provides a method for monitoring a patient at a central location,as indicated generally at 300 in FIG. 22. The method is implemented bysoftware running on patient monitors 22, central stations 24, and/orother components of system 20. The method includes, at step 310establishing wireless communications between a patient monitor and acommunications network having at least one wireless transceiver and aplurality of central stations. Then communicating a list of the pluralcentral stations to the patient monitor via the wireless transceiver, asindicated at step 320. Alternatively, the list of the plural centralstations may be provided to, or stored on, the patient monitor in otherways. In any event, method 300 proceeds with selecting, at the patientmonitor, one of the plural central stations, as indicated at 330. Thencollecting, at the patient monitor, vital signs data from a patient, asindicated at step 340. The vital signs data are communicated to thewireless transceiver, at step 350, and then communicated from thewireless transceiver to the selected central station, at step 360.

[0167] A further method for monitoring patients according to the presentinvention is indicated generally at 400 in FIG. 23. Method 400 includes,at step 410, establishing communications between a wireless patientmonitor and a central station adapted to receive vital signs data from aplurality of patients. Configuring the patient monitor to collect vitalsigns data from a particular one of the plural patients, at step 420.Communicating a list of the plural patients from the central station tothe patient monitor, as indicated at step 430. Alternatively, the listof patients may be provided to, or stored on, the patient monitor inother ways. In any event, method 400 continues at step 440 withidentifying, at the patient monitor, the particular patient.Communicating the identity of the particular patient to the centralstation, at step 450. Communicating the vital signs data collected fromthe particular patient to the central station, as indicated at step 460.Finally, associating, at the central station, the vital signs data withthe particular patient, as indicated at step 470.

[0168] Another method for monitoring patients according to the presentinvention is indicated generally at 500 in FIG. 24. Method 500 includes,at step 510, establishing wireless communications between a patientmonitor and a central station. Collecting vital signs data from apatient at the patient monitor, at step 520. Communicating the vitalsigns data from the patient monitor to the central station, at step 530.In the event that communications between the patient monitor and thecentral station are lost, detecting that loss of communications, at step540. Storing at least a portion of the vital signs data at the patientmonitor while the patient monitor is out of communications with thecentral station, as indicated at step 550. Restoring wirelesscommunications between the patient monitor and the central station, atstep 560. Then, communicating at least a portion of the stored vitalsigns data from the patient monitor to the central station, as indicatedat step 570.

[0169] Another method for monitoring patients according to the presentinvention is indicated generally at 600 in FIG. 25, and includesestablishing wireless communications between a patient monitor and afirst central station, as indicated at step 610. Collecting vital signsdata from a patient at the patient monitor, at step 620. Communicatingthe vital signs data from the patient monitor to the first centralstation, at step 630. So long as communications between the patientmonitor and the first central station are maintained, the patientmonitor continues to communicate the vital signs data to the firstcentral station, as indicated at 640. However, in the eventcommunications between the patient monitor and the first central stationare lost, then wireless communications are automatically establishedbetween the patient monitor and a second central station, as indicatedat step 650. Finally, communicating the vital signs data from thepatient monitor to the second central station, at step 660. It shouldalso be noted that when a clinician using the patient monitor transferscommunication to a different central station, there is a transition time(presently that duration is in the range of about 5-10 seconds). Duringthat transition time, the patient monitor could be configured to storedata for later uploading to the different central station chosen by theclinician.

[0170] Another method for monitoring patients according to the presentinvention is indicated generally at 700 in FIG. 26. Method 700 includes,at step 710, establishing wireless communications between a patientmonitor connected to a particular one of plural patients and a centralstation. Communicating the identity of the particular patient from thepatient monitor to the central station, at step 720. Collecting vitalsigns data from the particular patient at the patient monitor, asindicated at 730. Then, communicating the vital signs data to thecentral station, at step 740, and associating, at the central station,the patient monitor with the particular patient, as indicated at step750. So long as communications between the patient monitor and thecentral station are maintained, the patient monitor continues tocommunicate the vital signs data to the central station, whichassociates the vital signs data with the particular patient, asindicated at 760. In the event communications between the patientmonitor and the central station are lost for a period of time,reestablishing the communications between the patient monitor and thecentral station, at step 770. Then, automatically determining, at thecentral station, whether the patient monitor is still connected to theparticular patient, as indicated at step 780. Finally, if the patientmonitor is still connected to the particular patient, then associatingthe patient monitor with the particular patient.

[0171] In addition to the exemplary methods for monitoring patientsdescribed above, it will be appreciated that the configuration andoperation of system 20 is not limited to the exemplary methods as manyvariations and modifications are possible within the scope of theinvention. Further, system 20 may be configured and operated to monitorpatients according to a variety of other methods within the scope of theinvention. Therefore, it will be understood that all such methods,variations and modifications are within the scope of the invention.

[0172] It is believed that the disclosure set forth above encompassesmultiple distinct inventions with independent utility. While each ofthese inventions has been disclosed in its preferred form, the specificembodiments thereof as disclosed and illustrated herein are not to beconsidered in a limiting sense as numerous variations are possible. Thesubject matter of the inventions includes all novel and non-obviouscombinations and subcombinations of the various elements, features,functions and/or properties disclosed herein. No single feature,function, element or property of the disclosed embodiments is essentialto all of the disclosed inventions. Similarly, where the claims recite“a” or “a first” element or the equivalent thereof, such claims shouldbe understood to include incorporation of one or more such elements,neither requiring nor excluding two or more such elements.

[0173] It is believed that the following claims particularly point outcertain combinations and subcombinations that are directed to one of thedisclosed inventions and are novel and non-obvious. Inventions embodiedin other combinations and subcombinations of features, functions,elements and/or properties may be claimed through amendment of thepresent claims or presentation of new claims in this or a relatedapplication. Such amended or new claims, whether they are directed to adifferent invention or directed to the same invention, whetherdifferent, broader, narrower or equal in scope to the original claims,are also regarded as included within the subject matter of theinventions of the present disclosure.

We claim
 1. A wireless medical telemetry system, comprising: at leastone wireless patient monitor configured to collect patient vital signsdata; and at least one central station adapted to establishcommunications with the at least one patient monitor via a wirelesstransceiver, and to receive the patient vital signs data from the atleast one patient monitor; where the at least one patient monitor isoperable by a user to transmit an end-communications signal to the atleast one central station; and where the at least one central station isconfigured to terminate the communications with the at least one patientmonitor in response to the end-communications signal.
 2. The system ofclaim 1, where the at least one central station is configured tocommunicate a confirmation of the end-communications signal to thepatient monitor.
 3. The system of claim 2, where the at least onepatient monitor includes a display device adapted to display a messageto the user in response to the confirmation.
 4. The system of claim 1,where the at least one central station is configured to continuereceiving the vital signs data until the communications with the atleast one patient monitor are terminated.
 5. A method for monitoring apatient, comprising: establishing wireless communications between apatient monitor and a wireless transceiver connected to a remote centralstation; collecting, at the patient monitor, vital signs data from apatient and communicating the vital signs data to the central stationvia the wireless transceiver; communicating an end-communications signalfrom the patient monitor to the central station; and terminating thecommunications by the central station in response to theend-communications signal.
 6. The method of claim 5, further comprisingcommunicating a confirmation of the end-communications signal from thecentral station to the patient monitor.
 7. The method of claim 6,further comprising displaying a message to a user of the patient monitorin response to the confirmation.
 8. The method of claim 5, furthercomprising discontinuing the step of collecting and communicating thevital signs data.
 9. The method of claim 8, where the step ofterminating is performed before the discontinuing.
 10. The method ofclaim 8, where the step of terminating is performed after thediscontinuing.
 11. A system for monitoring the vital signs of a patientfrom a selected remote location, the system comprising: at least onewireless patient monitor adapted to collect vital signs data from apatient; a medical telemetry network including a plurality of centralstations adapted to receive vital signs data, and one or more wirelesstransceivers adapted to communicate with the at least one patientmonitor; where the at least one patient monitor is operable by a user toselect one of the plural central stations, and to transmit a request toestablish communications to the selected central station via the one ormore wireless transceivers.
 12. The system of claim 11, where theselected central station is adapted to establish communications with theat least one patient monitor in response to the request, and to receivethe vital signs data via the one or more wireless transceivers.
 13. Thesystem of claim 11, where at least one of the plural central stations isconfigured to communicate a list of the plural central stations to theat least one patient monitor, and where the at least one patient monitorincludes a display device adapted to display the list of plural centralstations to the user.
 14. The system of claim 13, where the at least onepatient monitor includes one or more input devices operable by the userto select one of the plural central stations on the list.
 15. The systemof claim 11, where the at least one patient monitor is operable by theuser to select a different one of the plural central stations, and totransmit, to the selected central station, a request to changecommunications from the selected central station to the differentcentral station.
 16. The system of claim 15, where the selected centralstation is configured to terminate communications with the at least onepatient monitor in response to the request to change communications. 17.The system of claim 16, where the different central station isconfigured to establish communications with the at least one patientmonitor in response to the request to change communications, and toreceive the vital signs data via the one or more wireless transceivers.18. A method for monitoring a patient, comprising: establishing wirelesscommunications between a patient monitor and a communications networkhaving at least one wireless transceiver and a plurality of centralstations; selecting, at the patient monitor, one of the plural centralstations; collecting, at the patient monitor, vital signs data from apatient and communicating the vital signs data to the wirelesstransceiver; and communicating the vital signs data from the wirelesstransceiver to the selected central station via the communicationsnetwork.
 19. The method of claim 18, further comprising: communicating alist of the plural central stations to the patient monitor via thewireless transceiver; and displaying the list to a user of the patientmonitor.
 20. The method of claim 19, further comprising receiving aninput from the user selecting one of the plural central stations on thelist.
 21. The method of claim 20, further comprising: receiving asubsequent input from the user selecting a different one of the pluralcentral stations; communicating subsequently collected vital signs datato the wireless transceiver; and communicating the subsequentlycollected vital signs data from the wireless transceiver to thedifferent central station via the communications network.